THE FUNCTIONAL ANATOMY OF THE SKIN MUSCLES IN PHASIANINAE Thesis for the Degree of Ph. D. MICHIGAN STATE UNIVERSITY DAVID R. OSBORNE 1968 ___=_O "M i II MI I 129IIIIIIIIJIIIIIIIIII E This is to certify that the thesis entitled Functional Morphology of the Skin Muscles in Phasianinae presented by David R. Osborne has been accepted towards fulfillment of the requirements for PhD degree mm Georg J. Wallace Major professor [hm September 20, 1968 0-169 F'— i; J L’nDADV 4 Michigan State " ”'33 'Unh crsit)’ :1 i“ >4 ,, H"I T. I ~. ‘ t ‘ “‘-~“~h a t‘~..~...vu~:.. Q :‘rv-«rn the ev‘ ~>....s,-i.-..u .. 'u a 'V"‘I-. ~v~4 a w uvfl ' "1 ~-.:g‘. 6.. E! . gan- ., .. ~.~Ie‘ V 9" h._.3~ I ‘Qd: I A‘J e.: : ‘ u... ‘ '9‘». . ‘o“s 5:33.? o. Fw‘» P" e ha-‘-er C;S: a ;‘\ -- V - .‘Latej : ‘8'“. u 2-- o I- s I. L... u“\'\_ -‘ A y '1‘ Fa “nude. 'r‘. me o o“ a Q" A» ‘ ‘v. :ar" r- t “SJ ‘_*I. . ‘0 c ~‘V-. . ~+‘,r ‘ “‘J|‘S r o “I Q. ‘ s "\ 'v 4‘ .¢..“ EV..’: ABSTRACT THE FUNCTIONAL ANATOMY OF THE SKIN MUSCLES IN PHASIANINAE BY David R. Osborne Although a great deal of information is available concerning the descriptions, functions, causations and the origin and evolution of feather displays, little is known about the mechanisms responsible for positioning the feather in disPlay. Two categories of skin muscles associated with the feathers may be involved: (1) the striated dermal muscles and (2) the smooth feather muscles. This study was undertaken to describe the gross mor- phology of the skin muscles and attempt to determine their relationship to feather display. Feather displays and the gross anatomy of the smooth and striated muscles of the skin are described and compared among several representatives of 4 genera of the Subfamily Phasianinae. The Ring-necked Pheasant is used as a type for comparison with other forms. Deductions of muscle action are based upon morpho- logical evidence, from observations of feather movement ‘\ and ’ ' 9‘ fi" E:I.a..-na.rw _ - qn,~"fi* ‘ . infant.» C- ~ o '-':.~uv ‘lfi’e‘ rife v .C-—.A ' :—;~-.11 A 4-:~ v- ur.».3$-zeu DASH . uoara-‘l‘ ' , ,‘ ‘ 2" v- ‘ mun :E‘l:l: tran‘ 5‘ . TL 7 u. ‘nl‘ee f‘r‘ctl .L (I! O m n l ; 1 (D H U) D Y (D ”31128" d‘sh' a ue relatlfiup ‘iiiier {p ‘uScIES (3. Q "lakes C; ‘ h”: :act ~ua : - t led. ul tae ‘~ Sl'e 154‘ o. In "56;; r; i David R. Osborne during display and preening, and from experiments involving muscle stimulation and muscle extirpation in live birds. Examination of pterylosis showed few differences in the arrangement of the feathers among taxa. Differences in the relative thickness of the skin in different regions of the plumage among birds corresponded to the localization of specialized display feathers, to the enlargement of follicles and to the relative develOpment of the feather muscles. £319 is distinctive from the other forms in having intercalary downs present among contour feathers of the crown and pelvic tract. Three functional types of smooth muscles associated with the feathers are described: (1) musculoelastic tissue, (2) tensor muscles and (3) feather muscles. Musculoelastic tissue shows little variability among taxa. Smooth tensor muscles of the skin are of limited distri- bution in the birds I examined. They showed great varia- bility among taxa. All are attached to follicles of specialized disPIay feathers. The relative develOpment, pattern and arrangement of the feather muscles differ appreciably among pterylae in indi- vidual males of the same species. This appears related to the fact that feathers in different regions of the plumage on the same individual may assume different feather postures during display. ~ather mus: H It: 3: 1r, heme lcgcus ';::I’. sexes of tie b-un A- ‘Q~A “cu: v-.4 u about: S CE . .Av" F‘ ‘L P ‘ p .. a. :ea*re - e . “3 ‘1- » Q ‘ ““i‘w’ iccated ' . 3"“ Mamas for ‘1:. .' ‘t. David R. Osborne Feather musculature and feather displays were most simi- lar in homologous regions among different breeds of chickens and among congeneric species. The gross pattern of the feather muscles is similar in both sexes of the same species, but feather musculature is less well developed in the hens. This appears to be because hens sometimes perform feather displays that are similar to but weaker than those of males. Greatest differences in the size, arrangement and pat- tern of the feather and tensor muscles are found in homologous dorsally located tracts among males of different genera. This appears to be because most conspicuous feather displays in homologous regions in males entail strikingly different movements of the feathers. Results from preliminary eXperiments involving direct stimulation of the dermal and feather muscles demonstrated that the dermal muscles move the skin while the feather muscles move the feathers. The distribution and arrangement of the dermal muscles differ little in homologous regions among taxa. Histological examination of teased dermal muscles at the insertions revealed that they did not attach to the follicles; only smooth muscles do. Dermal muscles show little, if any, relationship to feather displays. Apparently they act to tighten the skin in particular regions of the body which in turn appears to be coordinated with other body functions. Finally, res :2i;fi:ations of :;::s for feather 0"... Q‘ ‘I .::..'.e:s possmre David R. Osborne Finally, results of this study strongly suggest that modifications of the feather muscles appear to be adapta- tions for feather displays in order to make movement of the feathers possible. This in turn makes particular regions of the plumage more conspicuous. THE FUN THE FUNCTIONAL ANATOMY OF THE SKIN MUSCLES IN PHASIANINAE BY David RQQOsborne A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Zoology 1968 17.151“; to . .OAtOgv-‘P‘ sov- Cav- | D _-.~.lnl $.H ‘V- I h 9 -,...,.- A; —.—-De UL n.‘ the :ar:us:r:p 5. Wallace a: * L. 4 u . . ‘ r ’ "' :‘r*! F." :: Dene -‘Aaa‘ U‘ V' ‘ s :uw‘v‘p a’q ‘ . ‘~“‘¢O- ”u D rd .' Au- ~.vn.: O A \:'-A V A :_ “‘“VLHa- ‘J fg ' ‘1 ‘ ‘VAA r ~ ‘ r” Usu‘u‘“.‘u ‘-\‘ d P . .~ ‘ 0: t tuSe ; "F A‘ ‘ J00 PC—er Su- t:‘ 5 ‘5‘)" saunter: of A V'Q‘hens .. ....-....\::15 State ‘v. 0,, _ a \V' —.‘_. \LJ ““P'Jbllshe .‘ u:‘.e“h ‘ " «we: hElp a: ACKNOWLEDGMENTS I wish to express my sincere appreciation to Dr. Peter Stettenheim for his interest, advice and aid throughout the course of this study and for perusing the several drafts of the manuscript. Appreciation is also eXpressed to Dr. George J. Wallace and Dr. Alfred M. Lucas for their critical review of the final draft and to Dr. Rollin H. Baker, Dr. James C. Higgins and Dr. Robert K. Ringer for their helpful sugges- tions. Special thanks are extended to Dr. George H. Lauff for use of the facilities at the W. K. Kellogg Biological Station, Michigan State University, and to Mr. R. D. Van Deusen, Mr. Joe Johnson and Mr. Ben Smith of the W. K. Kellogg Bird Sanctuary for facilities for housing birds and for help in procuring birds and caring for them. Gratitude is eXpressed to Dr. Alfred M. Lucas and to Dr. Peter Stettenheim of the Avian Anatomy Project, U. S. Department of Agriculture, Department of Poultry Science, Michigan State University for making available portions of their unpublished manuscript on Avian Integument. Special thanks are extended to my wife, Alice, for her patience, help and encouragement during the past four years. I am also indebted to many members of the Michigan Game Breeders Association who donated birds for this work. I am grateful to the faculty, staff and Mrs. Dale Henderson of the Department of Zoology of Michigan State University for their help. This study was supported in part by funds received from the Chapman Memorial Fund of the American Museum of Natural History and from the Society of the Sigma Xi. ii -‘----‘o-A~vf‘\' - --‘.A'~'.-J'..K'L ‘5‘.) “cu—ocean Q " ‘ ‘o .u...\.J o o o o A.‘ ' 3.:3ects. “A? '~"FQ'\-- J:-€ ‘bOt‘Al‘lo‘ I'VQFJ “AA-o— DH, 5.. H- n:- e. . JG: 5:17.12: Preparation H ..., 5- r~"‘.‘H-v “Menus“-.. . I vs ‘. . "3“- 5 .~..\ DISC -~..,-~ O ““R‘ J.‘ ”’P‘YA‘. o‘u' ACE? "bAI‘ TABLE OF CONTENTS Page INTRODUCTION . . . . . . . . . . . . . . . . . . . . 1 METHODS. . . . . . . . . . . . . . . . . . . . . . . 7 Subjects. . . . . . . . . . . . . . . . . . . . 7 Determining Feather Movements and Postures. . . 8 During Reproductive DiSplays . . . . . . . 8 During Preening. . . . . . . . . . . . . . 9 Determining Pterylosis. . . . . . . . . . . . . 10 Preparation of Skins. . . . . . . . . . . . . . 12 Determining Muscle Action and Function. . . . . 16 RESULTS AND DISCUSSION . . . . . . . . . . . . . . . 18 DESCRIPTION OF FEATHER DISPLAYS. . . . . . . . . . . 18 Ring-necked Pheasant. . . . . . . . . . . . . 18 Golden Pheasant and Lady Amherst Pheasant . . . 20 Domestic Chicken. . . . . . . . . . . . . . . . 25 Indian Peafowl. . . . . . . . . . . . . . . . . 31 Summary and Discussion. . . . . . . . . . . . . 36 MOVEMENT OF THE FEATHERS AND THE SKIN DURING PREENING. . . . . . . . . . . . . . . . . . . . 39 Summary and Discussion. . . . . . . . . . . . . 44 PTERYLOSIS . . . . . . . . . . . . . . . . . . . . . 46 General . . . . . . . . . . . . . . . . . . . . 46 Description for Phasianus . . . . . . . . . . . 48 Pterylae . . . . . . . . . . . . . . . . . 48 Capital tract . . . . . . . . . . . . 48 Dorsal cervical tract . . . . . . . . 48 Interscapular tract . . . . . . . . . 49 Dorsal and pelvic tracts. . . . . . . 49 Ventral cervical tracts . . . . . . . 50 Pectoral tracts . . . . . . . . . . . 50 Sternal tracts. . . . . . . . . . . . 50 iii 0 H1 r :n O-VI 5‘1 31 '(J r t (D '1 LL ‘L'I‘F‘OIX‘WLD (.1 TI (1) TABLE OF CONTENTS--continued Abdominal tracts. . . . . Lateral body tracts . . . Femoral tracts. . . . . . Crural tracts . . . . . . Humeral tracts. . . . . . Subhumeral tracts . . . Posthumeral tracts. . . Alar tracts . . . . . . . Caudal tract. . . . . . . Apteria. . . . . . . . . . . . Lateral cervical apteria. Ventral cervical apterium Scapular apteria. . . . . Lateral pelvic apteria. . Lateral body apteria. . . Pectoral apteria. . . . . Sternal apterium. . . . . Crural apteria. . . . . . Median abdominal apterium Lateral abdominal apteria Interscapular apterium. . Comparison. . . . . . . . . . . . Summary . DERMAL MUSCLES Introduction and Review of the Literature Materials and Methods . . . . Abbreviations . . . . . . . . . . . REVIEW OF THE DERMAL MUSCLES . . . . . M. constrictor colli. . . . . . . Description for Phasianus. . . Innervation. . . . . . . . . . Comparison . . . . . . . . . . The Cucullaris Complex. . . . . . . M. cucullaris pars cranialis. . . . Description for Phasianus. . . Comparison . . . . . . . . . . M. cucullaris pars dorsocutaneus. . M. cucullaris pars prOpatagialis. . M. cucullaris pars omocutaneus. . . M. cucullaris pars metapatagialis . M. cucullaris pars cervicalis . . . Description for Phasianus. . . iv Page 51 51 51 51 52 52 52 52 52 55 55 55 55 55 55 55 54 54 54 54 54 54 64 66 66 7O 71 72 72 72 72 75 75 75 74 76 76 77 78 78 78 79 erxal Co: H.1atiss: Descr Inner orpa. M.latiss;: Descr: Inner' U .H a :r ’(J T.) TABLE OF CONTENTS--continued Cervical component. . . . . . . . . . . . Clavicular component. . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . Innervation . . . . . . . . . . . . . . . Dermal Components of M. Latissimus Dorsi . . . M. latissimus dorsi pars dorsocutaneus . . . . Description for Phasianus . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . M. latissimus dorsi pars metapatagialis. . . . Description for Phasianus . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . M. latissimus dorsi-omocutaneus. . . . . . . . Dermal Components of M. Serratus SUper— ficialis. . . . . . . . . . . . . . . . . M. serratus superficialis pars metapatagialis. Description for Phasianus . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . M. serratus superficialis pars dorsocutaneus . Dermal Components of M. Pectoralis . . . . . . M. pectoralis thoracica pars subcutaneus thoracicus. . . . . . . . . . . . . . . . Descriptionfiof Phasianus. . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . M. pectoralis abdominalis metapatagialis . . M. pectoralis thoracica pars subcutaneus abdominalis . . . . . . . . . . . . . . . Description for Phasianus . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . Other Striated Muscles Associated with the Skin . . M. gastro—lumbalis . . . . . . . . . . . . . . M. mylohyoideus posterior. . . . . . . . . . . Description for Phasianus . . . . . . . . Innervation . . . . . . . . . . . . . . . Comparison. . . . . . . . . . . . . . . . Mm. occipitalis, frontalis, dermo-frontalis, circumconcha and dermo-spinalis . . . . . Page 79 79 80 81 82 82 82 85 85 84 84 85 85 85 86 86 86 87 87 87 87 87 88 88 88 89 89 90 9O 9O 91 91 92 92 95 95 105 ure'w CCNTBNTS .slad.‘ V ‘ lC MLCIOSCO IT) p h,~,..oqr‘ r? 3-“..-‘-¥Uatb 4 b l -. c — Att.on o- *.. Morp:3. p‘pvv Vf'“ on: any- ~ E"‘"€"" I.“ oov . "V n-un’ . ‘ O‘°¥‘O~Au\.u‘3r .. Femoral .“. C1 r4 TABLE OF CONTENTS--continued Microsc0pic Examination of Teased Dermal Muscle Significant Morphological Findings. . . . . . . Action of the Dermal Muscles. . . . . . . . . . Morphological evidence . . . . . . . . . . Physiological evidence . . . . . . . . . Evidence from muscle extirpations. . . . . Summary and Discussion. . . . . . . . . . . . . Relationship of the Dermal Muscles to Feather Display. . . . . . . . . . . . . . . . . . SMOOTH MUSCLES OF THE SKIN . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . Femoral Tract. . . . . . . . . . . . . . Description for Phasianus . . . . . . Comparison. . . . . . . . . . . . . . Crural Tract . . . . . . . . . . . . . . Description for Phasianus . . . . . Comparison. . . . . . . . . . . . . Lateral Body Tract . . . . . . . . . . . Description for Phasianus . . . . . Comparison. . . . . . . . . . . . . . Humeral Tract. . . . . . . . . . . . . Description for Phasianus . . . . . Comparison. . . . . . . . . . . . . . Ventral Capital, Ventral Cervical, Pector- al, Sternal and Abdominal Tracts; Musculoelastic Tissue . . . . . . Description for Phasianus . . . . . Comparison. . . . . . . . . . . . Dorsal Capital, Dorsal Cervical, Inter- scapular, Dorsal and Pelvic Tracts; Musculoelastic Tissue . . . . . . Dorsal capital tracts . . . . . . . . Description for Phasianus . . . . Comparison. . . . . . . . . . . Gallus . . . . . . . . . . Chrysologhus . . . . . . . Pavo . . . . . . . . . . . . Dorsal cervical tract . . . . . . . Description for Phasianus . . . Comparison. . . . . . . . . . . Gallus . . . . . . . . . . Chrysolophu . . . . . . . £232 . . .-. . . . . . . . . Interscapular tract . . . . . . . - Description for Phasianus . . . vi Page 105 105 110 110 114 118 125 152 156 156 158 158 149 150 150 151 156 156 159 159 159 160 165 165 175 176 176 176 178 178 181 184 185 185 188 189 195 205 205 205 I-r— _.~ V Sorcery f I Smooth auscul: Feather Tensor Action of t? Muscult Feather Tensor I m) crw-m VJ'VL '0 q ‘~:~':": YrV-h ~0.Heh..~‘ $.L TABLE OF CONTENTS--continued Comparison. . . . Dorsal and pelvic tracts. Description for Phasianus Comparison. . . . £222 - - - - Musculoelastic tissue Summary of the Descriptive Morphology of the Smooth Muscles . . . . . . Musculoelastic tissue. . . Feather muscles. . . . . . Tensor muscles . . . . . . Action of the Smooth Muscles of Musculoelastic tissue. . . Feather muscles. . . . . . Tensor muscles . . . . . . SUMMARY AND CONCLUSIONS. . . . . . . LITERATURE CITED . . . . . . . . . vii Page . . 215 . . 214 . . 214 . . 216 . . 218 242 . . 243 . . 245 . . 244 252 255 . . 253 . . 256 . . 265 . 267 . . 279 l‘ a c n..- 4 g“- I J.- (.r‘ C —J (1’ {A} ’A “V- Czcurrence < Lengths cf : tracts of :72 R 111‘ ‘y. ‘ Vaggu ' C-.r' Occurrenc pheasants . Origin, 1256 muscles . . Responses of rival males 13:15 n~ HGIS " ‘7‘ . .al’.a.1gn O: V: 'w'h .ewt of f ”:SLaT‘HJS r~ \‘ D‘“ . I“ ‘ "Ces A avrsal Cey.,‘ f‘nl ‘n‘l (D ['1’ t) LIST OF TABLES Table 1. 2. 10. Occurrence of feather ruffling during preening. Lengths of feathers within various feather tracts of male Phasianus colchicus, Gallus gallus, Chrysolgphus pictus and Pavo cristatus. Occurrence of dermal muscles in 4 genera of pheasants . . . . . . . . . . . . . . . . . . Origin, insertion and course of the dermal mUSCleS O O O O O O O O O O O O O O O O O 0 Responses of cock Rhode Island Red chickens to rival males after partial removal of M. cucul- laris pars cranialis. . . . . . . . . . . . . Variation of muscle volume, feather length and weight of feathers in the pectoral tract of Phasianus colchicus . . . . . . . . . . . . . Differences in the feather musculature of the dorsal cervical tract in males of Phasianus colchicus and Gallus gallus . . . . . . . . . Mean weight and length of 6 feathers from the mid—region of the dorsal cervical tract of adult male Phasianus colchicus, Gallus gallus and ChrysolOphus pictus . . . . . . . . . . . Weight of muscles of‘6 feathers from the mid— region of the dorsal cervical tract in adult male Phasianus colchicus, Gallus gallus and Chry5010phus pictus . . . . . . . . . . . . . Lengths and weights of 16 consecutive feathers from a right chevron arm of the mid-region of the pelvic tract of a male Indian Peacock (Pavo cristatus). . . . . . . . . . . . . . . viii Page 41 65 106 107 124 .167 190 191 192 222 1:57 or TABLES--Cf I. 1 ‘ ' ‘ ’.-. Re.atlonsr.1p . ., an: wezgnt c of a sale In LIST OF TABLES--continued Table Page 11. Relationship of muscle weight to feather length and weight of 2 feathers from the pelvic tract of a male Indian Peacock (Pavo cristatus). . . . 225 ix .wuy .ova. G 'U (I. '7 Ffitre-F~ r: .. LVu-\.3..¢p u Pneasant. . 1 \§ u.POst.IES 0: between at: I~‘ 1 '2. ‘d‘era‘v fl“ flrufi‘. ,_ ~ I r‘ . ‘la‘~l\e.ls \Ju v. Feather KC... IndLan Peaf 1") 0 Lateral VLe sten' ‘~* 3? Ste 5 R 0 Y, F.- , 'esagral "y; 'v- ~3W1no J E: pte (I) o Dorsal V163 I F SAACWLng pp ‘3 ¥ & (‘) o M _ ImerHal I." CAT.‘ A ‘1 a M‘Ml“~‘s S :2: atta-‘lr... A Q "'\ «V0 IratEErVAa‘l . A ‘U' “' Le‘r . l ' ~ (‘3 U P — LIST OF FIGURES Figure 1. 2. 10. 11. 12. Courtship display of the male Ring-necked Pheasant. . . . . . . . . . . . . . . . . . . Courtship diSplay of the male Lady Amherst Pheasant. . . . . . . . . . . . . . . . . . . Postures of a dominant male chicken assumed between attacks dUring agonistic behavior . . Lateral, frontal and attack displays of male chickens during agonistic behavior. . . . . . Feather movements and postures of the male Indian Peafowl. . . . . . . . . . . . . . . . Lateral view of a male Phasianus colchicus showing pterylosis. . . . . . . . . . . . . . Ventral view of a male Phasianus colchicus showing pterylosis. . . . . . . . . . . . . Dorsal view of a male Phasianus colchicus showing pterylosis. . . . . . . . . . . . . . Internal view of the skin of male Phasianus colchicus showing the course, distribution and attachment of the striated dermal muscles associated with the dorsal pterylae . . . . . Internal view of the skin of male Phasianus colchicus showing the course, distribution and attachment of the striated dermal muscles associated with the ventral pterylae. . . . . Left lateral view of the head and neck of male Phasianus colchicus showing the super- ficial musculature and the origin of the derm- al muscles. . . . . . . . . . . . . . . . . . Dermal and superficial muscles of the trunk of male Phasianus colchicus . . . . . . . . . Page 24 24 28 50 54 56 58 60 96 98 100 102 VVL'O A 503‘ '- a”? 5.1e J ()4 O . § 0“ Q‘. r\. I I \J '95. . J F FIGURE: Ext rnal tthh of feather IT. Dissectior ' ‘l‘ ‘ 4 10111216 ; "L X I- C. boae ‘lle: LIST O Figure 15. 14. 15. 16. 17. 18. 19. 20. 21. 22. 25A. F FIGURES-econtinued External view of the skin covering the left thigh of a male Phasianus colchicus showing feather muscles of the femoral tract. . . . . . Dissection of feather muscles associated with 4 follicles in the mid-region of the left femoral tract of Phasianus colchicus. . . . . . Dissection of feather muscles at the caudal border of the left femoral tract of a male Phasianus colchicus . . . . . . . . . . . . . . External view of the left crural tract of Phasianus colchicus showing the arrangement of feather muscles . . . . . . . . . . . . . . . . Dissection of feather muscles associated with 4 follicles of the middle of the medial surface of the left crural tract of Phasianus colchicus External view of the skin covering the lateral surface of the body of Phasianus colchicus showing feather muscles of the left lateral body tract. . . . . . . . . . . . . . . . . . Dissection of feather muscles associated with 4 follicles in the mid-region of the left humeral tract of Phasianus colchicus. . . . . . Relationship of muscle volume to weight and length of contour feathers in the right pector- al tract of Phasianus colchicus . . . . . . . . Internal view of the skin from the ventral side of the body of male Phasianus colchicus showing the feather muscles . . . . . . . . . . . . . Internal View of the skin from the dorsal body of male Phasianus colchicus showing the feather muscles . . . . . . . . . . . ... . . . . . . Diagrammatic representation of M. tensor pterylaescapitalis dorsalis of a male Phasianus colchicus . . . . . . . . . . . . . . . . . . . xi Page 141 144 147 155 155 158 162 169 172 180 185 LIST OF FIGURES - I“. a"? I . ‘Udo I Ix) u» Ix) (1) (‘\‘) [\f) (I) l\) (1 I O 2!- I .Dissection 4 crest f: pO-IV v...‘ 0 0 m (D () r'f LY I (D BIS. GOES: capztal a: - Internal :- external e cape feat? show;ng t? muscles -Dissect13r ' Schema: Vy. (Al one of the lateral c: n - ic thtrathr Cape feaek aTTav .‘ “‘S External I scaplliar . SMOWlY‘n I 8.3 EuSCles '\ Dorsal 'v. n; " 7‘ an 64 “all. ‘4 y‘ ch av LIST OF FIGURES--continued Figure Page 25B. Dissection of feather muscles associated with 4 crest follicles of a male ChrysolOphus pictus. . . . . . . . . . . . . . . . . . . . 185 24. External view of the skin of the dorsal sur- face of the head of a male Pavo cristatus showing feather musculature of the crown feathers. . . . . . . . . . . . . . . . . . . 187 25. Internal view of the skin from the dorsal sur- face of the neck of male ChrysolOphus pictus showing feather musculature of the cape feath— ers, dorsal cervical tract and parts of the capital and interscapular tracts. . . . . . . 199 26. Internal view of the skin between the right external ear Opening and follicles of the cape feathers of a male ChrysolOphus pictus showing the arrangement of the protractor muscles . . . . . . . . . . . . . . . . . . . 201 27. Dissection of feather muscles associated with one of the outermost follicles of the left lateral cape of Chrysolophus pictus . . . . . 205 28. Schematic representation of the course of the protractor muscles and the movement of one cape feather from a non-display position to a display postion in a male Chrysolophus amherstiae. . . . . . . . . . . . . . . . . . 207 29. External View of the middle of the inter- scapular tract of male Phasianus colchicus showing the gross pattern of the feather muscles . . . . . . . . . . . . . . . . . . . 210 50. Dissection of feather muscles associated with 7 medial follicles of the interscapular tract of a male Phasianus colchicus . . . . . . . . 212 51. Dorsal view of the skin covering the pelvis of an adult peacock showing pterylosis of the pelvic and part of the dorsal tract . . . . . 229 xii N: Hams-- sci. V. r. a"? _ -l to 4 1° Internal V; Hi. ”5 ,, agnle V. M U“-- the pelv1: «Q n. sternal v; I ‘..‘. Ob n aaux- ‘ 1 the pe4vzc m ~ * . 8488:8311 1 (h) Internal v; of an ads“ CLes of the dorsal tra: 9 .pp 1 o ‘11. rial 1": - t V o 0. an a"“ ' 0 “VA 5 0-..- Q . b..e peL'V'lC ~ 1 V I o ..33$211te3 (’1 (P) LIST OF FIGURES~-continued Figure 52. 55. 54. 55. 56. 57. Internal view of the skin covering the pelvis of an adult peacock showing feather muscles of the pelvic and part of the dorsal tract. . . . Internal view of the skin covering the pelvis of an adult peahen showing feather muscles of the pelvic tract and part of the dorsal tract. Reflected light. . . . . . . . . . . . . . . Internal view of the skin covering the pelvis of an adult peacock showing the feather mus- cles of the pelvic tract and part of the dorsal tract. Transmitted and reflected light Internal view of the skin covering the pelvis of an adult peahen showing feather muscles of the pelvic and part of the dorsal tract. Transmitted and reflected light. . . . . . . . Dissection of feather muscles associated with 4 follicles of the anterior mid-region of the pelvic tract of the peacock. . . . . . . . . Dissection of feather muscles associated with 4 follicles in the lateral mid-region of the pelvic tract of the peacock. . . . . . . . . . xiii Page 251 255 255 257 259 241 'v-fll" ( ) ysfi“fln P‘ .-~'-v.a V‘ a _ . I n ' ‘ “i A V‘ ‘ .- ‘ f‘ " .0 3v... "y Me.- , ’ 7 . ;.,.~ 9A 4 , i....-"SbV‘ I ‘v O ‘. l .-- ‘3. v- .:::.' o Fea‘”e“ LS a generalize: A‘r\ _""v-,l b are in the Z ‘V‘ A’ ‘L ‘ f' .. «...e Cnazf‘. "“ ,‘A ”A a ’1 .nn': Lu .OrrLS \- .3 II‘C' f. ‘ . Les 3 ( fl. ..“- : ~Cuperca111we ‘ l- n “We 7- ‘ were Bird- 7“. ...e 31'1ng I 4. “ T ‘q c 5, ~\ ‘ I] ‘unctlf‘v v’n hr Iq‘lzatlzr ll ‘. f ‘ :': ~ ‘:V' ‘5 Lscm pF'V‘~. IV“ . t“. . ~‘ieragl INTRODUCTION The positioning of body feathers during display has been the subject of numerous investigations in avian behavior. Descriptions of feather displays occurring during courtship or agonistic behavior have been reported for many birds (Hingston, 1955; Stoner, 1940; Andrew, 1961; Armstrong, 1965). Feather displays may be non-specialized in which there is a generalized raising of all body feathers, occurring for example in the Zebra Finch, Poephila guttata (Morris, 1954) or in the Chaffinch, Fringilla coelebs (Hinde, 1955). Accord- ing to Morris (1956), feather displays may also be special- ized where exaggerated movements of body feathers are restricted to certain areas of the plumage (e.g., the ruff of the Great Crested Grebe (ggdiceps cristatus), the crest of the Sulphur-crested Cockatoo (Kakatoe galerita), the "beard" of the Capercaillie (Tetrao urogallus), and the "eye" tufts of the Superb Bird-of-paradise (Lophorina superba). The origin and evolution of display functions from non- display functions were first termed by Huxley (1925) as "ritualization". The origin and evolution of feather dis— plays from non-signal functions have recently received con- siderable attention (Daanje, 1950; Morris, 1956; Tinbergen, Q "9 ;;;A. Ana: {54.-I *"Val ‘ .. fe-ther (1:55:15?!s p i mom" durlnfi' tne guy“ I)» -F..,.~av\‘ . , a," H AALV“ -...~nn b . . . 3937.12 U18 '38 S C .-~ ‘ . . . :..: EZQILCICT‘. c ‘ ‘ Opp- 1...: messamsr. “v we categ:r - O . :r‘np- ' bi...\-‘S an: a '(1 CI :‘Fa+ «.a. are the de: ~ :LIS‘ A fly- I— ‘ - “ESs-«lue: : 3“; u. T'Y‘v- «1., FL? . ‘ ‘9~ ~atea t.- d 4' a I~ ‘ yd t 0‘ L. .L a - U- “r v. "‘e 8“.“ ‘$Llo T ‘1 kn 1 .. R" "v. 95 ‘5 arf" ‘ A.“ a P! - mes ‘éz-Le “m: V .H ‘ P“ S I ‘ cles I .547} 1' " l l'fik 1 An ad. E’l“:“ t. ..'r C: c t e~‘_ t I: -f'e: ‘. :‘(E‘ 'h. u- 1952, 1954; Andrew, 1961). It is generally assumed that feather displays are derived from feather movements which occur during thermo-regulation (Morris, 1956); but feather movements which occur during preening and shaking of the feathers, shaping the nest cup and during defecation are also considered as possible sources (Andrew, 1961: 558). Although a great deal of information is available con- cerning the descriptions, functions, causations and origin and evolution of feather display, little is known about the motor mechanism responsible for positioning the feathers. Two categories of skin muscles are associated with the feathers and appear to be involved in feather movement. First are the dermal components of body muscles, apparently first described by Jacquemin (1856). These striated muscles are innervated by spinal nerves, originate from the skeleton or a part of a body muscle, and insert onto the under surface of the skin. The second category includes the smooth feather muscles and a deeper network of musculoelastic tissue. The feather muscles, apparently first described by Nitzsch (1840), link adjacent feathers and are innervated by the sympathetic (Langley, 1904; Ostman t al., 1965a) and pos- sibly the parasympathetic nervous systems (Ostman §t_§l,, 1965a). Feather muscles are located within the dermis. Very little is known about the arrangement and distribu- tion of feather muscles in birds. Brief descriptions were given by Seuffert (1862) for several birds of prey and mterff‘fie’l 0 He I: " c L :3”, feathers, re. Essie-ed and £1; 35165 in the Ma 523' the Crested s Publisned '4 : 1 15:11 and featne CI. afiayyy ard flpFCH A . iovhv. . . .Pn .... extensrse der' ‘V ‘n-ckuv -- b» r‘ ‘ s nab-v-y.'5 aus_§d;fi H ‘1 1:221 51'. lees off "" (a ‘ ,I h‘ .m: .‘s C‘. u.- t ‘ ukler . . phraae Was . It was Lark ~ Zlfe II: .t 5 5| «kuf‘en ar’: : .551; I“r n.. l'SfllL ' 55 ‘: Pate:- ,. Se VU Y9 . vgie S":~ 'vJL'F A b... and r‘ “A t ‘Du \ ._S: waterfowl. He found feather muscles associated with contour body feathers, rectrices, remiges and down. Lowe (1955) described and figured the gross arrangement of the feather muscles in the Magellanic Penguin, Sphenicus magellanicus, and the Crested Screamer, Chauna torguata (Chauna salvadorii). Published information concerning the action of the dermal and feather muscles in feather movement is contra- dictory and confusing. Owen (1842, 1866) related the distinct and extensive dermal muscles in the South Island Kiwi (Apteryx australig) to the burrowing habits of the Species which shakes off loose earth from its plumage while excavat- ing its chamber. Helm (1884, 1886) examined both the dermal and the feather muscles in numerous birds, but his account of the feather muscles is brief. He concluded that the size of the feather muscles varied over the body with the size and frequency of feather movement and that the action of these muscles was to assist in the ruffling and laying down of contour feathers. He also concluded that a ruffling of the plumage was possible with the dermal muscles. It was Langley's (1904) detailed analysis on the struc— ture, innervation, and action of the feather muscles in the chicken and pigeon which focused attention upon the feather muscles as functioning to position the feathers. After observation and stimulation of the sympathetic nervous SYStem and spinal nerves, he concluded that the feather nmscles act to erect, depress and retract the feathers, .gereas demal m: an .- :‘Ler d‘Spla feisola‘. of tr: . .329 5" 'la ‘7"; rife?“ e a or e ‘ vo:‘-F\" 5‘ *‘F ‘- “..'.‘ V‘ kite ta- ecu-“RY fins/#40- a; a; .15.: ...e 08117815 'L-- we sectoral L s... —..:=L ' 55 “1"” «‘S e...“ c. .C whereas dermal muscles twitch the skin without producing feather erection or depression. A search of the literature reveals very little infor- mation on the relationship of the dermal and feather muscles to feather display. Hemming (1844: 212), in his analysis of the display of the Indian Peafowl (Pavo cristatus), reported that the small muscles between the quills of the train were inadequate alone to raise and spread the train and that ele- vation of the tail played the major role in elevating the train. Viallane (1878) stated that two dermal muscles, M. temporo-alaire (= M. cucullaris pars prOpatagialis) and M. fronto-iliac (= M. latissimus dorsi dorsocutaneus), were responsible for the display in the Superb Bird-of-paradise (LOphorina superba). Similarly, Pycraft (1905) concluded that the dermal slips of M. pectoralis controlled the eleva- tion of pectoral feathers in the display of the Lesser Bird- of-paradise (Paradisea minor). He also noted strands of "minute" muscle passing from feather to feather but did not comment on their role in diSplay. Stettenheim _£.3l- (1965: 920), in a comprehensive study of the arrangement and action of the feather muscles in Single Comb White Leghorn chickens (Gallus gallus), found that feather musculature was heaviest and most complex on the dorsal region of the neck. They re— lated this to the fact that the most conSpicuous displays of these birds entail pronounced raising of the hackles. Several factors may account for the lack of knowledge concerning the action of the skin muscles in positioning the - .006- fevers. First 5:313:31 anato. ;:::e:“.‘re is to 5:21“. the feather :e oerrzal muss). :ve s‘-tl:_qed v.5..— buUA ‘ s... R- ' .71 1' 2e fom--ate .L‘ u§ ‘ A».-S odd}, :a‘V'e Ccl if.» .L I ‘ "“»-l .L ““u ‘Vuneu * . ,. (“Fit . ~ Cf .o It: a", : :‘ris gla'v, F ”W. “-45 semi. 5 H V. .‘.A n" v- ‘. § ‘eeatl’w ‘r. V4. ‘.‘: :‘(7I '-.| ‘3 ea‘L‘Er :. n p.‘ “5:11" Peas. -‘ ‘a: by h 5““: ‘- I .‘3‘ \ .‘I‘ey .C-Hr. _ “NEE"- '.,. ‘c. «“ I “‘Q‘ '?~ 1dr~ ~ ‘ «Q‘ ~. “ feathers. First, in many studies on the descriptive and functional anatomy of the appendicular muscles the common procedure is to remove the skin and discard it. In this way both the feather muscles and some of the insertion ends of the dermal muscles are lost. Second, if the dermal muscles are studied without examining the skin, erroneous conclusions can be formulated on muscle course, action and function. This may have contributed to the confusing descriptions which I found in the literature on the dermal muscles. I know of no thorough morphological investigations on both the dermal and the smooth muscles in a closely related group of birds having different habits. Also, subsequent to Langley, I know of no studies involving observation and eXperimentation on muscle action and feather movements in live birds. This study was undertaken in an attempt to determine the relationship of the striated and smooth muscles of the skin to feather diSplay in certain representatives of the Subfamily Phasianinae. Birds of this group were selected because they represent a relatively closely-knit group taxonomically, are of large size, are easy to maintain in captivity, and because they possess modified feathers such as crests, hackles, capes and trains which are displayed during courtship or reproductive fighting. My hypothesis is that differences in feather display are related to morpho- logical variations in one or both categories of skin muscles. The genera angle ccnb Whi , ~ Q I -..,.. P "'7‘! Al ' - . ."..:.—-a..a bes$b4ue Imam Peafowl p a —..'.. .. ‘.t..::.a,'._,s c: p_.; ( J .41.: to 5: Saar; 5'-;.3:ltles 3:}: dental a..d feat? . .qvo Ctser.‘a“ .fl'. (~U ‘ - 3-3.; “H c “ _ ‘1! a. u «: The generalized and specialized feather displays of single comb White Leghorn, bantam Rhode Island Red and Araucana chickens (Gallus gallus), Golden and Lady Amherst Pheasants (Chrysolophus pictus and g, amherstiae), the Indian Peafowl (Pavo cristatus), and the Ring—necked Pheasant (Phasianus colchicus) will be described. An attempt will be made to standardize the terminology of the dermal muscles. Similarities and differences in the gross morphology of the dermal and feather musculature will be compared and related to feather display. The action of the feather and dermal muscles in moving the feathers will be deduced from morphological evidence, from observations of feather movement during display and preening, and from experiments involving nerve and muscle stimulation and muscle extirpations in live birds. l“:""ara arr: I— p-a a.“ L! all - n.‘~pfi 7"; L:~., ‘1 J"‘“"" 1“ a“: I - . i a~FQV ‘wac‘ in ‘ _‘ v Q .T ‘ .3 tie abet: re; :Oo.,. --‘-..e genus. f‘ K. A “WAY... HI I.-~ | I ~‘Q‘F‘ ‘ fi‘b4 ‘ I.‘ P .s, «for u,.‘ ~uu~u :e F ‘ ‘N a.“ _. .F .4- METHODS SUBJECTS Birds used in this study were captive adult Ring-necked Pheasants (Phasianus colchicus), Single Comb White Leghorn, Araucana and bantam Rhode Island Red chickens (Gallus gallus), Golden and Lady Amherst Pheasants (Chrysologhus pictus and Q, amherstiae), and Indian Peafowls (Pavo cristatus). For the sake of brevity, generic names used in the text refer to the above representatives of the genus and not to the entire genus. Chrysolgphus, when used, refers to both ChrySOIOphus pictus and g, amherstiae. Nomenclature for the pheasants is from Delacour (1951). Descriptions for Phasianus are presented first, then comparisons are made with the other representatives. Single Comb White Leghorn chickens were obtained from the Department of Poultry Science at Michigan State Univer- sity, East Lansing, Michigan; the bantam Rhode Island Red and Araucana chickens, peafowl, Ring-necked and ornamental pheasants, from local game breeders. All birds were of known age and many were utilized for several different as- pects of this study. The study we Stxuary, Kalazm hi;K:erst Pheg ‘ v A’ ?’ eran‘n,‘ in ‘hl-e 3‘UU.IU . . 7 . a :‘JKLIES, an: 'na. .:p.‘ l’ 'V ' h?‘ N! ‘ ‘A \ 56 : v d-.u.\.... ‘ 1.. . ‘ .-r~r\" cfi'ga‘.fi.“ ' ..... u ‘ w :rfifl‘zl Ar . A-J...‘ V; l k - a“; s u- a r‘ r.‘ ’ suns-s uu“nj C :nnfl. ‘: - lI ‘ ~:‘-~.ES Hur.ng a\‘ In”! " :~':S el¥r.er a 8; ~'. ‘. _ ...€ S“5,9Ct. '~. :AP. A \ ‘ cues Vf (leaf;i va. IE": I... 'b " ““9 beer. . Q: ‘F0 1 .1 Seozarllx, ‘ I :5 The study was conducted at the W. K. Kellogg Bird Sanctuary, Kalamazoo County, Michigan. Breeding pairs were housed separately in an outdoor aviary, but several male Lady Amherst Pheasants and a trio of peafowl roamed freely on the grounds. Food, a sanctuary preparation of commercial mixtures, and water were readily available. DETERMINING FEATHER MOVEMENTS AND POSTURES During Reproductive Displays Frontal or lateral displays are given by males toward females during courtship and toward other males of the same Species during agonistic behavior. In the display the male gives either a side or frontal orientation of the body toward the subject. Both frontal and lateral displays include move— ments of head, wing, tail and feathers. Although these dis- plays have been described previously for numerous members of the Subfamily Phasianinae (Seth-Smith, 1925; Beebe, 1951; Huxley and Bond, 1941; Delacour, 1951; and Shenkel, 1956, 1958), little is known about the localization of specialized display feathers, the form and extent of feather movement, and the movement and postures of non-display feathers. I often initiated disPIays by introducing new birds to males already acclimated to females in the cage. Since the sanctuary is frequented by many pe0ple, most birds became readily adjusted to the presence of humans. For this reason a blind was not required for observing the displays. Observation '22:: during t ::'.'e:.e:ts and p: =' ‘3 frames per 4- av ::st‘.‘:es that ce ;'.‘."' t V. 1 “Rh-“I “5.8 Se- A ‘ ' 3.81.8 t3; :os.r ‘. A bu»..e seq“ Eye :-;'.. 4 ch “ Y ‘s ...:ZEu ‘v. ‘5“ D l V I .__ “a lu,‘ CC... Pr .eOh‘ n C‘.‘ F: 'O I "~..; A l“‘ P‘ 0's ‘4 D . ~l .. ._ ‘ c ~ § .H‘ \- v .N‘egr‘ F,‘ '0 "u v 3.. "t‘ib. V o‘ »‘ 4‘ 'I‘lr.rs «g A. h: ”a .. 'r. ““"V a ._'1 N I Observations were made in the early morning and late evening during the spring of 1965, 66, and 67. Feather movements and postures were photographed on 8 mm movie film at 18 frames per second and examined later at full, Stop and reverse speeds. Frames which showed the various feather postures that certain regions of the plumage assumed during display were selected to make the drawings. Since this is not strictly an ethological study, the entire sequence of reproductive behavior patterns is not analyzed for its functional implications. Rather, emphasis is placed upon describing the extent and form of movement of the body feathers as a basis for explaining muscle action. Movements of the wings, body and tail were noted but were considered of secondary importance to movements of body feathers. In descriptions of feather postures I followed the terminology of Morris (1956: 80). In some instances new postures, not mentioned by Morris, had to be named and described. Other behavioral terminologies are from numerous sources (Andrew, 1961; Dilger, 1962; Etkin, 1964: 206-227; and McKinney, 1965: 125-150). During_Preening I made observations on feather movements and postures during preening of aviary birds and compared them with my observations of feather movements of homologous regions during display. These observations were made at a distance ’1‘. :53 feet or more Observations were also made 1r. SLTgie-CCITIJ Whit 5:;:;Late bira‘s t ‘ Q I OV‘H‘RSFR r .- h-v‘.U&u‘: “ea; 0 s V ::e :znute eacn t i.’ (A (I) *3 :1 "1 (D (‘D (3' D '1 ‘1: be ..';:e a say for a liup '5' cu. ‘ . ‘ I‘m-U .U.:!V‘3ed tr.E .VI. - c ‘ _.....;<.e: .rcm area ‘I‘rn‘a ~‘=‘~P€1'~'ic and a 93%;?- so that t‘ 3?." n -~1- - . on ¥:dv‘a De C: ‘ l:2 ‘ we U ‘Eet. l'. bl ‘ A \ 22:.” b I ll a..d ,r~ ‘8 .- c I x 7“ ‘Hf‘l 1‘.“ f3.! .4 4! FC‘L‘ G" F fisher fly . s‘ U l-‘ ‘II: N‘. 10 of 10 feet or more from the subject. Observations of feather movements during preening were also made in the laboratory on partially defeathered Single-Comb White Leghorn chickens. I found that I could stimulate birds to preen by wetting the plumage and then providing heat. After being held under tap water for about one minute each bird was placed in a 15" x 24" x 15” wire cage. Three birds were observed individually for 20 minutes twice a day for a period of 5 days. A loo—watt goose-neck lamp provided the heat. Groups of feathers were clipped or plucked from areas of the dorsal cervical, interscapular, dorsopelvic and femoral tract, thus forming gaps in the plumage so that the stubs of individual feathers and the skin could be observed. Observations were made at a distance of 5 feet. DETERMINING PTERYLO S IS Pterylosis is defined as the distribution of feathers on the skin (Harrison, 1964: 670). Contour feathers may be uniformly distributed on the skin as in the penguins (Spheniscidae). However, in most birds feathers grow from definite tracts (pterylae) on the skin with intervening bare areas (apteria). Pterylosis of many birds was described by Nitzsch and Burmeister (1867). In this study I have followed the terminology of Lucas and Stettenheim (1965: 3). Feather tracts are visible only on the skin. Plucking and clipping of the feathers, examining study skins or . ‘1235' and t A" 'p! and " .'..‘.‘- Fave been .I‘.“‘ u t. ’ ‘ g tms 5‘»L .er tYaCts 1 “p I '7 ‘1 K“ ‘ ‘45 .u 3.( .nL‘ a -:I-‘ ‘5'1 ‘ ‘ ~‘:.“~a‘ ‘le¢no I 4" 1 ' I‘ A .:...c. ta" \. ~ n'hfl“ . A“ . .. “.th {65.23.- ' uni-F. . F h~qu A: 1.; EC'Ji'The .:;.r.er release. As V" hue CC: 3;: .6 make" \A I..." :‘::l-.S 'w' y n e. e tan:- 11 nestlings, and using soft ray X-rays are different methods which have been used to determine the pattern of feathering. The advantages and disadvantages of these methods have been discussed by Heimerdinger (1964). In this study contour feathers were plucked from feather tracts in birds anesthetized with Equi-Thesix’ (2.5 to 4.7 ml/Kg body weight) injected intravenously into the basilical vein. A light plane of anesthesia as defined by Fedde, _£_§l, (1965) was used. At this plane of anesthesia a chicken responds to pinching of the comb, but shows no response to pinching of the skin or toes. After administra— tion of Equi—Thesi$§>the feathers in the follicle are loose and easily plucked. The action of Equi-Thesié:>appears to be similar to that of tranquilizing drugs (Sturkie §£_gl,, 1958) and other anesthetics (Ostman §£_§l., 1965b) in affecting feather release. As the contour feathers were removed, each follicle was marked with India ink. Follicles of downs located in apteria were not marked due to the small size of the follicle. Photo- graphs were taken of the marked bird and the negatives were used to produce the drawings. One disadvantage of this method of determining pterylo- sis is that it is very tedious and time consuming. Another is that it was difficult to mark the small, numerous follicles located on the skin covering the head. An advantage of this method is that the marking of follicles and then photographing the bird provides a visible ‘ r'fi’ . ; tn 9 ' ram 3. ,.e " . V‘ :ared tract by t‘ 1 A A‘ A" ’y y. 5.5. aids -... -e jgs;:2at 3‘? Part; d ..n ‘ ..‘ I:..’.Cl€$ fer SJ- 0 ‘ ‘ ;w~>hs v‘e- ~h? 6‘s." bA‘ l ‘H.. ¥ . C 9- ‘ ,. O. ‘ .. .ne CaDltaL. a ’~‘... . ‘ 0...».e: .rcm trls K ::;:‘.1.K~'.TICN OF SI- n.2I‘eQ ~ and a» w . +u «urn. MJSCL a‘ A L b.“ “l “ r.‘ “" 31:” cuu‘~s ac‘ aLE' C .s '. “-.:C.? .0 v" 12 record of the gross pattern of pterylosis which can be com- pared tract by tract to the distribution of the follicles and skin muscles of other representatives. This method also shows the relative size of the feather follicles in different regions of the body. It was especially useful for designating particular rows of follicles and individual follicles for subsequent determinations of their feather lengths, weights and muscle mass. The gross pattern of the body tracts is first described for Phasianus and then compared with the other forms. Details of the capital, alar, subhumeral, and caudal tracts are omitted from this study. PREPARATION OF SKINS Skins were prepared from fresh, frozen and alcoholic specimens. In all instances fresh material produced a better preparation. In alcoholic specimens, feather and dermal muscles were often too brittle to dissect and often were distorted and appeared to be in various states of contrac- tion. Musculature was often deteriorated in specimens frozen for more than 2 years. All live birds were killed by over-anesthetizing with Equi-Thesié:)rather than by cervical dislocation, bleeding, or by the "stick" method of King (1921). Feather tightening results after death by cervical dislocation (Peterson and Ringer, 1963) and bleeding (Klose gt. 1., 1961; 1962). 0:0f‘rts to .- rv e-‘V‘ 00a es 385“ 9;: Zing r 355:" feat 19‘: t I u I. ‘ 0 Le featner H.353 kLL'. birds in an v Q (I. 1‘ it; (1.4 a state a ;L'.‘:?.eéf rrcr: ti" e Skins were ; 15:221.;9. de"el::: :ftfet. s pep, “:b.-nos at MlCHir ‘ Skin ccntarr .‘40 «f L‘ ‘ ‘t ‘ I ‘ a. v L .e Gertie: 3:. wire cloth an: a“ 25 :.a:;al acetic a' :JS dGPEHdlng‘ t. ‘n -.y“ '1 mac and 3517-5 were th 15 My efforts to "stick" birds were not successful. Over- anesthetizing results in a loosening of the feathers after death (Peterson and Ringer, 1965). The same mechanism that affects feather tightening may affect the contraction of the feather muscles. Hence over-anesthetizing was used to kill birds in an attempt to have the feather muscles in as relaxed a state as possible. All contour feathers were then plucked from the body. Skins were prepared for examination according to the technique deve10ped by Dr. A. M. Lucas and his associates of the U. S. Department of Agriculture Avian Anatomy Investi- gations at Michigan State University.1 Skin containing the feather muscles and the insertion ends of the dermal muscles was removed in sections, mounted on wire cloth and fixed in Bouins fixative (75 parts saturated picric acid, 25 parts formalin--full strength, and 5 parts glacial acetic acid). Time of fixation ranged from 5 to 12 hours depending upon the thickness of the skin. During fixa— tion picric acid stains the muscle tissue a light yellow. Skins were then removed from the wire cloth and stored in 70 per cent ethyl alcohol until dissections could be made. Carcasses were placed in crocks containing 5 per cent formalin. Two changes of fluid were made after several weeks. lThe citation refers to the manuscript of "Avian Anatomy. Integument," currently in the process of final editing; the manuscript will be published for the U. S. Department of Agri- culture by the Government Printing Office. ‘- ”I..." t. .:.;asses were t.. I. 3m ethyl a1 ‘ ‘f‘ V I...y A0? ”a?" . '- ,bel .‘o. 3'. . d the unpleasant v: 25525 pliable a were reexam: :‘1. iii the birds we: I éet name: attazl'rtent to t‘m :scles to the f. ‘~ ’ c; , ~ :‘E :: .&)sej 5“ I "‘“wR 4 ‘VU¢.U ashes frcm the {'rl- c .. '-~.:‘.e A ‘h V‘ t..e : ;. ‘u- . n. A‘Na'. mdmteut ard . I ‘. I» .‘h‘e S\ ynr,‘ I \ 1;. ”a R'L‘ "‘a A‘ I 6. {Eat “is 4 ‘E‘ V'» e‘oulne ‘Ere S‘ 14 Carcasses were then stored in embalming fluid (78 parts 70 per cent ethyl alcohol, 20 parts glycerin, and 2 parts of full strength formalin). The embalming mixture eliminated the unpleasant volatile odor of formalin and made the tissues pliable and easy to work with when the dermal muscles were reexamined. No mold or bacteria formed in the crocks and the birds were preserved satisfactorily for 5 years. I determined the insertion, course, distribution, attachment to the skin, and the relationship of the dermal muscles to the feather follicles by examining the under sur— face of fixed skins. I found it easiest to examine and dissect the feather muscles from the internal surface. This required removing the dermal muscles, connective tissue, excess fat and the larger peripheral nerves and blood vessels from the under- surface of the skin. The gross arrangement, distribution and pattern of the feather musculature, as viewed with the unaided eye, was described first. Finer details of the arrangement and the pattern were then determined by dissection at the subgross level with the aid of a 0.7 to 50 power Bausch and Lomb stereomicrosc0pe. Muscle type (striated or smooth) of teased muscles attached to the feather follicle was determined with the light microsc0pe. Teased muscles were stained with hematoxylin according to standard histo— logic procedure. -1 LT. certain regi: estrated by dete I detertme: 5:11;:le by meas; 55:: crssectea r: N'DAI AWPn . ‘ou.=u°évats CC t: J ‘ 1 irntp Af P'" ‘ .».A~:L..s V (HUSCL ' ( ‘l U S ' ‘ C); "fi '1 ( ) P h ( ) ‘—‘ F r A :J m U) U) C) P 9“ 15 I attempted to determine whether a relationship existed between the degree of muscle develOpment and feather size in certain regions. The degree of muscle develOpment was estimated by determining muscle volume or muscle weight. I determined the volume of the muscles of a particular follicle by measuring the length, width and thickness of each dissected muscle with a micrometer, multiplying these dimensions together and summing the values of all rows. The lengths of muscles, including the tendons of attachment, were measured from follicle wall to follicle wall. The width and thickness of the muscles were measured at the belly. Prior to determination of muscle mass the skins were washed in 70 per cent ethyl alcohol for 25 minutes to remove the picric acid. For skins which were excessively fatty the alcohol treatment was preceded by a 15 minute wash in chloroform. Individual muscles were dissected free, removed, grouped as to muscle type (erector, depressor or retractor), air dried for 24 hours and weighed to the nearest 0.1 mg with a Mettler H16 balance. Feathers were weighed to the nearest 0.1 mg and feather length was measured from the inferior umbilicus to the long- est barb to the nearest millimeter. Feather muscles were examined in day old Ring-necked Pheasants in order to ascertain the degree of development of this system in newly hatched birds. Nomenclature for the dermal muscles is reviewed in a later section. I have followed the terminology of George and 55::er (1355) for L534} and Stetter ‘ ' .Aflf " .«:-_~:\'a'\‘:.\G M: by“ y‘.-,.-.0 Analysis of ‘ - “"‘ F a ’V‘ A I,‘ nun-A ' S ”a... ‘ ._-C Uu'vib“ nu‘ul SESCILVE {63535. 11 r.;;::r.eses and 1:; I've-’- ..:_..ti'.eses have k; :e:?.:‘ of fret i" .abb J 2"Av- ‘ 3. the laws -: 5'. 1 . v. .“e retatl'b'e fl \. ....e:er.t habits "in AC ‘w \- V‘ attaCE‘re' u,“ ‘~...q I'JSf‘ ~ ' \y 165 c uLEf‘P 'f‘ toe-.ges are 4 a Dee-3.13:5 16 Berger (1966) for the tongue and jaw musculature; Langley (1904) and Stettenheim §£_al, (1963) for the feather muscles. DETERMINING MUSCLE ACTION AND FUNCTION Analysis of the functional significance of the dermal and smooth muscle components is, by necessity, based on deductive reasoning. Conclusions on muscle action are only hypotheses and must be treated as such. Only after the hypotheses have been tested by extensive experiments can they be relied upon, and even then there is a chance that some important factor has been overlooked. The deductive method of functional anatomy is based partly on a consider— ation of the laws of mechanics and partly on a consideration of the relative development of the muscles in forms having different habits. For example, if the distribution, course, mode of attachment, shape and mass of certain feather or dermal muscles differ among representatives which have differ- ent feather displays, then the basic assumption is that these differences are somehow associated with feather display. Deductions of muscle action and function in this study are based primarily upon morphological evidence. Evidence is also obtained from preliminary experiments involving muscle and nerve stimulation and extirpations of certain dermal and feather muscles in live birds. In the experiments on muscle stimulation, birds were lightly anesthetized with Equi-Thesi$:)(2.5 to 4.7 ml/kg body weight). If respiration ceased, birds were given ..,..-l:e;:;cnal a -..0‘ 1‘7 'E'HLJ'Je 05 B“ L. .3“: and feat . V L m ‘y‘“ “. .5. gnaw“ - ‘ 1 23. $33.31 IDCIS b .‘p.~‘(;p IV A ~a' ~...».s\pt- 0 k‘ ‘ :te stmlus. D .... n5 H— 4- ..vu UL Late St ‘0‘ :'V O~~~~‘ 56’5“ us ......latlv.. the text. . ‘~ ‘4 IA“ I ‘ounu ‘ :..:..;.1I‘..5 tC 5: "rs r ‘ ‘ :-»:e:»ec lint trne n. ,‘ st: '1», ‘ ‘ “we: to - \‘ .,, | 5" ‘y. ' . ES 1“: 5 cc . ‘CQ> Htg, Cfl"rl‘~‘ vxl.‘v‘ . I . n ‘ I. c '5 ‘I ‘ 1.," “hp. I v-- \wg. a 17 unidirectional artificial resPiration according to the technique of Burger and Lorenz (1960). The eXperiments were designed to provide information concerning the action of the dermal and feather muscles in positioning the skin and feathers in different regions of the body. The method of Langley (1904) was used to stimulate cervi- cal spinal roots, peripheral nerves and dermal muscles in chickens. A Harvard model 9358 stimulator was used to supply the stimulus. Details on the strength, frequency and dura- tion of the stimulus and the selection of dermal muscles for stimulation in this experiment are presented later in the text. The technique used and difficulties encountered in attempting to stimulate the feather muscles in chickens are presented in the section on smooth muscles. To determine the function of the dermal and feather muscles in display, unilateral and bilateral extirpations of certain dermal or feather muscles associated with special— ized display areas of the plumage were performed in anes— thetized chickens and Golden Pheasants. After the Operations birds were allowed to recover overnight. They were then resubmitted to agonistic and courtship situations. Similari- ties and differences in feather movement during display kwtween controls, experimental and sham Operated birds were noted and compared. -‘ r- 911* L22. -_ " AMEIL’E’E P113! to 3e :: :resent a br; ;:s::res. Mcrr; - . Op P . my featr.er - 2|;q :Y‘f‘?~:| .‘l‘u ‘V. “A 33‘! erected a:; if” 1»; ‘ ~I5 Ullese featr| r. a, s u‘“r1 . a3‘3‘1’ (F; ::x“ V ‘ "I m- ‘ 1:13 . ‘:.:IV‘:‘ a. ‘ I ' x ‘A C‘Sp‘au'. RESULTS AND DISCUSSION DESCRIPTION OF FEATHER DISPLAYS Prior to describing feather displays it may be helpful to present a brief review on the terminology of feather postures. Morris (1956) describes 4 basic postures which the body feathers can take during display. Starting from a relaxed (=normal) posture, feathers can be depressed tightly against the body to give a sleeked posture, or elevated slightly to produce a fluffed posture. When feathers are fully erected and the tips of the feathers are spaced wide apart so as to give a jagged appearance to the plumage, they are then in a ruffled posture. It is important to realize that these feather postures differ primarily on the degree of their elevation from the surface of the body. Ring-necked Pheasant A lateral courtship display is given by males toward females during the breeding season (Figure 1). Prior to the display (Figure 1-1), the male is usually in an upright posture. This posture is also assumed between consecutive lateral displays. In the upright posture both wings are Slightly lowered and the rump feathers are exposed. 18 feathers are azct're "ear“ tuf "Ear" tufts “er-entary st: on uv " an 1 external ear Cpe: ~ I :25: (Frures 1, P's!- are At “r ‘ nu h . O l' .. Ear tafts :2::"‘G:. DMSV‘lA‘ g;; .V A. g. e fr gr.ter.e: fixage. "Ear .. 1 :ztegtrettary " ea 19 Body feathers are in a normal position, the tail is compressed and the "ear" tufts are elevated and inclined outward. "Ear" tufts are feathers which arise from two accessory integumentary structures ("ears") located dorsal to the external ear opening on the dorsal lateral surface of the head (Figures 1, 7, 23A). They serve no auditory function. They are not present in hens. "Ear" tufts are often maintained in an elevated and inclined position throughout the breeding season. When males become frightened, they are lowered with the rest of the body plumage. "Ear" tufts appear to move as a unit, as if the integumentary "ears" were involved. Tips of the feathers do not appear separated from one another as do feathers which are fluffed or ruffled. During the lateral display (Figures 1-2 and 1-5) the male is crouched, feet together, with neck bent and head low, as close to the hen as possible. Wattles of the face are flushed deep red. The tail, tilted toward the hen, is Spread. The inner wing (i.e., that closer to the female) is lowered somewhat further than the outer wing. Body feathers are fluffed. There also appears to be a general swelling of the body. This may be caused by inflation of the air sacs and may result in some movement of the feathers. The dorsolateral orientation of the body appears to be accompanied not only by a general fluffing of the body feathers, but als :lcsest to the he regicn. Shifting. :es:.t in a 5113': v='-F aw): I‘L.’ ~% A.“ .u—u “H 50-.j‘; Un- . Stnce the 23 Liseccné , the s ieterntne even fr Elfin; of the f O - . I: "z‘flv‘ u“. U , T" F . adji A‘e“ a a: .I '9 e hi." o .‘ .‘M.d S"~C. § ‘|-‘_ x s.‘ ..r- " u a“ ‘ ‘ ThICC";‘c--t . “-0 a ‘VU V.‘ Di ‘4. ‘ "tilec. Her C ‘ C1 ‘ ['5‘ ~ ' ' ‘vi Dc . u _ u ,. V t - $ ‘ ‘c‘. 20 feathers, but also a shifting Of the plumage to the side closest to the hen. This is most noticeable in the rump region. Shifting Of the plumage to one side appears to result in a slight separation Of the feathers between the rump and thigh on the Opposite side. Since the lateral display is brief, lasting from 5 to 15 seconds, the sequence Of feather movements is difficult to determine even from movies. My Observations suggest that fluffing Of the feathers occurs just prior to swelling Of the body. Then as swelling increases, the dorsolateral aspect Of the body is tilted toward the female, the plumage Of the rump shifts and separation Of the feathers occurs on the Opposite side. Throughout the lateral display the hen is usually relaxed. Her feathers are normal and she stands in a some- what low position. I did not Observe any attempts at COpu- lation after the display. - Other feather movements, apparently not associated with the display, appeared to be related to the extension and retraction Of the head and neck, and involved feathers cover— ing the neck. For example, as the head was extended, feathers of the neck moved apart but did not alter their vertical position relative to the surface Of the body. Golden Pheasant and Lady Amherst Pheasant The lateral courtship diSplays Of male Golden Pheasants and Lady Amherst Pheasants are very similar. NO differences ‘ a k 6‘ were a;,aren . be . ~. .4. ;..-.r'rveed in C3; .n-C.Hc Several gestures Pniierst male are a'hen there a .5..':1 ”firefly.- :v-AC.‘. JU-. a. 5 '(1 9' . ‘ ‘. net tne bacx cs: :._:. Crest. car "'I I: #‘ “ ...e an. tne tall q .1 tn the preser « u n n 9......" ' ‘ “:va.”’ the 3.8L} we case are ex" .. ,PF p; “‘5 ‘ “‘w ‘ V :a‘e‘el'!) I .. c r "U. x; . .Eq_hev ,r, U. 2»; r 'y‘ 5“] V, . pf‘n. . db A. , '0. v ’u "‘:v‘ u ‘ "Vvs qu Ut-’ ) at ’A5 _: Eru ' .4 21 were apparent between the two species either in the form or the extent Of the display. Both species are known to interbreed in captivity and the hybrids are fertile. Several postures in the courtship display Of the Lady Amherst male are shown in Figure 2. When there are no females present the male assumes a general upright posture (Figure 2-1) with his wings folded over the back concealing the bright yellow feathers Of the rump. Crest, cape and body feathers are in a relaxed pos- ture and the tail is compressed. Between lateral displays, and in the presence Of hens, both wings are lowered slightly, exposing the yellow feathers Of the rump. During pursuit Of the hen (Figure 2-2), feathers Of the cape are extended slightly forward and upward, equally, on both sides to the level Of the mandible. Body feathers are in a relaxed posture. The male pursues the hen with his head and tail extended. At the height Of the lateral display, when the head Of the male is as close to the face Of the hen as possible, his body is arched and tilted toward her. His head and neck are slightly extended with the bill pointing upward but completely hidden from her view by full extension Of the cape feathers on the side closest to her (Figures 2-3, 2—4 and 2-5). Positioning Of the cape feathers is the most conspicuous aspect Of the feather display. Cape feathers are not erected perpendicularly from the surface of the body , ,-. ‘eathers w‘r . :. a“ L in. “4:125 of the c .u. ‘n ‘ ‘. ~ ~ . e latera. :..,..- ... l ”.4: "nvv VA tOv 'nr‘f; 1.06 an. LU *LA. u . ~v‘Arw‘ v r “A ouoonA-g SUredJ “ :5 ;ara.;el to tr 3:...eslcerl CL. ‘* . 7‘ ’1 wt.“-‘ll4 ‘- 7 b. 5:55:15 than 1' 1 F? 22 as in feathers which have a ruffled posture. Movement Of the tips of the cape feathers is downward from the neck, along the lateral surface Of the head, and then anteriorly and upward toward the eye. It results in a conspicuous and uniformly Spread fan (Figure 2-5). The movement Of the cape is parallel to the long axis of the body. As in the Ring-necked Pheasant, the display is accom— panied by swelling Of the body and shifting Of rump plumage. However, shifting Of the plumage is more noticeable in Golden Pheasants than in Ring-necks. The tail is slanted and spread only on the side facing the hen. The wing on this side is lower than the wing on the Opposite side. Feet are always placed one in front of the other, depending upon the side displayed. When displaying t0 the left, the left foot Of the male is placed forward. The display is fully lateral. When the hen is in front Of the male the male arches his body and curves his tail around her (Figure 2-4). Either side Of the cape can be §££§QQ§Q. At no time did I Observe both sides Of the cape fully extended together, nor did the crest feathers elevate. The lateral display is held as long as the head Of the hen is near the face Of the male. Only after the hen moves away does the cape partially retract and the body plumage return to normal position. Hissing occurs during swelling (Hithe body. The lateral display lasts for several seconds, the time depending upon the position of the hen. Once I 23 Figure 1.--Courtship display of the male Ring—necked Pheasant. (1) Upright posture, (2 and 3) lateral display postures. Drawn from motion pictures. Figure 2.--Courtship display Of the male Lady Amherst Pheasant. (1) pre-display posture, (2) pursuit posture, (3, 4, and 5) lateral display postures. C--cape, D-— feathers Of the rump. Drawn from motion pictures. The number in parentheses refers to the number Of frames subsequent to the preceding posture. 24 necked _ra_l display :cznted 26 cons 125:1 ys follow ew ”‘ej 1 one.) as. “‘4 annu'. .....s several ' “u”... N... -2 .' ~§ u‘...'_..' K, ~«»..€T \ F'finfis‘. "'“¥M" e ‘ ‘ :I‘ -: e N}\q 1.." I! I bu. vl.‘gl‘ ‘. p OA~ ' Q “:39: ills: l a': ‘ 4 .. . IC'C z... H ‘ r" vow (““e I ““ an { ‘ uns‘h u... ' e :f: -u‘ k .A ‘ c 5" Cl.fer.3 : ZLEIQVen‘ . \‘ k I ‘-Q ‘ .“t ‘CYV~ m. "‘v-Q ”‘H‘ UV“‘| ::;.‘_ \Iscners are r ~ ‘ .. . N‘ ' § 1. .e ‘h 'u. y ‘ “IE-sq; “v; A \ 'b I‘V e S \ q;‘ ter 7 v“ 1 e“ . ‘ ‘ I «3‘ . I ‘ I I y -'~i~ 'r. . \‘§\‘ Fe 4 s \.~ . .. a . 1.5 3:;cc‘C ‘ :"'~‘ . ‘I‘L Ab; rah“ 5‘ U ‘ a '-. Mk,“ .F ‘ I :f~" ( J“. . {UHC‘N i “N ’3'». § 4 r. its”: ‘ i. p- d 25 counted 26 consecutive displays in a 2 minute period. When displays follow in quick succession, the cape Often remains fully extended while swelling and shrinking of the body occurs several times. Domestic Chicken Frontal, lateral and numerous other displays are given by male chickens during agonistic behavior. In determining feather displays during agonistic behavior, Observations were made using 6 male and 3 female Single-Comb White Leghorn chickens, 8 male and 5 female bantam Rhode Island Reds, and 1 pair Of Araucanas. NO differences were Observed in feather displays among the different breeds. When a rival male is introduced into the territory Of another, the dominant male frequently assumes an upright posture (Figure 3-1). In this pose the body feathers are relaxed. Often the dominant male will crow (Figure 3-2). During crowing there is a moderate fluffing of the breast feathers. Plumage falls back to a normal posture after crowing. I Initial challenge to a rival begins with a lateral dis- Play (Figure 4-1). During the lateral display the dominant Hale shuffles("waltzing9 Of Wood-Gush, 1954) toward the rival and presents the dorsolateral aspect Of his body to Ififlh Body feathers are fluffed and the outer wing is dropped close to the ground. Primaries are slightly sepa— rated. NO swelling Of the body was Observed, nor did I hear .- ma-Jii‘i" ' scunds prol Lateral displaj hethallenge l ‘ . “7:9“!‘n at ‘ =vo‘vvtnbtn 5 ‘ . .. ‘ PF.» h.'n ~‘--- “”3 sea: . mu... ,, 3.33.3: 383585 L ‘~~ A ‘v -v nu:.. ‘ 'W 1 Le bed 15“? .. -...e., hm l~ ‘1“; La :15“. I'- 5.3:5 are hr ‘ ‘§ A ‘5‘.“ ‘v. “3.3, d‘sn‘ . ‘ I .. ‘ vl‘a . v I u- ,y ‘ .. the C A 1038* . s '7. ol._| :‘p g“ “. duar‘. 'v O ‘5 fi 7. fi'fi" ‘ ‘tvnta! a. N U; 2‘ ‘. Cb”: ‘( s ‘ il‘ ‘ U‘all u ‘L ‘ I .....2 f7"; 4 no, ‘¢ int. , L, , ...: "M; Q ‘HS s.“r~ H~‘l. 26 any sounds produced. The rival either counters with a lateral display Of his own, submits by avoidance, "ignores" the challenge by redirection activities (e.g., pecking or scratching at the ground; "tidbitting" Of Domm and Davis, 1948) or assumes a frontal display. In the frontal display (Figures 4-2, 4-3, 4-4, 4-7, 4-8) both birds spar bill to bill with heads extended and tails somewhat depressed. Hackles Of the upper neck are fully ruffled while the rest Of the body feathers are sleeked. Wings are folded and slightly lowered, but are held tightly against the body. In general, except for erection Of the hackles, both birds appear streamlined for flight. Frontal displays are brief, lasting for several seconds. In addition to ruffling of the neck feathers during the frontal display, ruffled feathers Of the neck were Observed to move closer together when the head was retracted and further apart when the head was extended. Frontal displays are almost always followed by the attack display (Figures 4-5, 4-6), which is usually initiated by the dominant bird. This display is essentially frontal and involves flight and body contact. Hackles remain ruffled and the rest of the body plumage is sleeked even during flight. Attacks are frequent and last until one Of the birds submits: normally it is the introduced male. The lateral display is dispensed with when attacks are con— secutive. I Observed frontal displays and attack occurring 27 .mmxmnmlpmmn m>flusummcoo N cmm3umn onmuw mo Hogans on» On mummmu mflmwnpcmumm OH HOQED: Hm3OH osu amusumom mcflpmooum on» CD ucwsvmmnsm mmEmum mo HOQESC may Ou mnommn mammnucwumm OH Hones: momma one .mmusuoflm COHDOE Eouw :3mun .NCHBOHU Adfilmv .mxmnmlmmmn flaw NUOQ Asumv .mGHBOHU ANV .musumom unmflumn Aav .HOH>man Uflumflcomm mcfluzc mxumuum cmmBqu Omasmmm cmeflnu mama ucmcfleop m MO mousumomll.m musmflm 28 ks? MI I' m musmflm 29 .musumom mcflpwomnm mnu ou ucmsqmmflsm memuw mo HOQEDC on» ou mummwu mammsucmumm OH Hogan: one .mmusuOHm cofluoe Scum CBMHQ .xomuum Amumv tmemmHU Hmucoum Ami» Ocm OINV .memmflO HmnmumH Adv .HOfl>m£mQ Uflumflcomm OOHHDO mcoxOHnu mama mo mhmHmmHO xomuum 0cm Houconm .Hmumumqll.¢ onsmflm w musmfim VLQW'" .‘i_\ l'l Ll: (I u In." C: .u‘. i. d ' ‘ "I ‘7; Av- ’ N" vl.‘ , 7n 4., “‘ bl 31 only during the breeding season and only when hens were present. Between attacks and frequently in the presence Of other males, the dominant male sometimes ruffles his feathers, jlgpg his wings and shakes his body (Figures 3-3 through 3-7). Feather ruffling occurs over most Of the body. Hackle and breast feathers are the first to ruffle. During the bggy— shake the tail is depressed and the head is slightly retracted. Usually three rapid wing-flaps and two head-shakes to the side are given (Figures 3-4 through 3-6). Body-shaking begins with the head and ends with the tail. Often the body-shake is immediately followed by crowing (Figures 3-7 through 3-11). Hackles and breast feathers are the only feathers I observed to ruffle during crowing. In two instances I Observed frontal displays between cocks and hens. Both cocks and hens raised the feathers of the upper neck; however, the extent Of elevation was much less in hens. Indian Peafowl The elaborate courtship display Of male peafowls is chiefly frontal. Feathers most conspicuously displayed are those Of the lower back. Collectively referred tO here as the train, these feathers are long and conceal those Of the tail when the bird is not displaying (Figure 5-2). The term tail as used here includes both the pygostyle and the tail feathers (rectrices) and their coverts. {.5 club ‘hu ‘1 g :'.-\ : ~ MAI "‘“"»q. ' 'L . .91 ‘ l I '7'»- QuU L.‘ e D. ‘HAC A "q lllH‘¢«..a K WM ” UV. 32 The male prepares for display by retracting the head and bracing the feet. The bird then leans forward until the breast is almost touching the ground. The tail, with the rectrices spread, is swiftly raised to about 45 degrees and the train moves upward and forward (Figure 5-3). Two to three short flaps Of the tail are given as the train is elevated to its maximum angle (about 87 degrees). Fan—like spreading Of the feathers Of the train occurs as it is being elevated. Anterolateral—most feathers extend forward and downward to the ground. Feathers of the train can be main- tained in the elevated and fanned posture for as long as 40 minutes. If the train drOps much less than 87 degrees it is reelevated. Wing-fluttering occurs after the train is elevated and and fanned. During wing-fluttering both wings appear relaxed and the primaries are separated. Both wings flutter in unison. Both peacocks and peahens appear to have permanently erected crests, at least I never witnessed one with the crest depressed. Courtship displays are given during the breeding season, Vflmther or not females are present. I saw peacocks display- ing to captive Great Horned Owls (Bubo virginianus), hen Ring-necked Pheasants, and hen Golden Pheasants. Peacocks di3played primarily in the early morning and late evening. fkmever, I frequently saw them displaying during mid-day when the sky was overcast. 33 Figure 5.--Feather movements and postures Of the male Indian Peafowl. (1) preening of the back, (2) non-display posture, (3-7) courtship display, involving elevating and I”. spreading Of the train to an elevated and fanned posture. "A Drawn from motion pictures. The number in parenthesis refers tO the number Of frames subsequent to the preceding posture. 34 male (10) n-disphy ting and losture- esis recedifi (Io) Q) A 7 My Figure 5 I observed 3 the displaying ma] 5-5) the tail was oft‘ne train lastl 22;; as the male tight of the dis anip'xsued the h Stressful. i. appeared the elevation of 535'!- The short rectrices against. 3?“ exsla‘in the ai.:rizenta1 resr 5L. "*5 we: 9 Ute, r "any of the . 35 I Observed 3 attempts at COpulation. On each occasion the displaying male approached the hen by backing toward her. He then turned, faced her, crouched low and positioned the train well forward over his head. In this pose (Figure 5-6) the tail was vibrated and the train rustled. Rustling Of the train lasted from 2 to 5 minutes and was performed only as the male leaned forward toward the hen. At the height Of the display the male shrieked, lowered the train and pursued the hen. The 3 attempts at copulation were un- successful. It appeared that elevation Of the train was related to the elevation Of the tail and the shaking of the posterior body. The short rapid flaps Of the partially spread rectrices against the undersurface Of the train feathers might explain the method by which the train is elevated from a horizontal resting position to a vertical position. If this were true, removal Of the rectrices should alter the capacity Of the train to elevate. I tested this theory in one male. When the rectrices were clipped close to the skin, the bird could still elevate. Spread and rustle his train. I could not detect any notice- able differences between the experimental bird and a normal bird in the elevation and spreading of the train except that shaking of the posterior body appeared to be slightly more intense in the bird with the clipped rectrices. Ikmmver, the shape of the fan, as viewed from the side, was pita irregular in the irregularity o braced against the 23:11:; was less These obse va -. 5 ‘ ' .snc. sepehaent u rizcrnly shaped f l u ‘9 OI ...e feathers . i 55’ P “E; '. DJ Fl 1‘) (D C 2.. v w‘ Sl‘h'u - A nag! an“ 0‘ cfi“ \TA . JV 1" setsulflca ”Li-'5 we \ a. u C . ar‘V ' \ .ZAR nu ‘n d; Cc «“erey‘. 1“ 'q‘ it‘;:'b I analong b‘ L Izr.‘ {"3 “FES § . \ hlsc J ~ I 1“”:: ‘. v- ‘5 GP ‘I‘lt r e3ln 4 un: ?~ ‘« A? taut PO' 1 u h #AJI S ~. ‘ . :.:" ct \ . ”M‘A‘ DL‘J " I 36 quite irregular in the clipped bird. This could be due to the irregularity of the stubs of the rectrices which were braced against the shafts of the train. I also noted that rustling was less intense than in an unclipped bird. These Observations suggest that elevation Of the train is not dependent upon the flat surface Of the rectrices. The Spread rectrices may aid in maintaining the train in a uniformly shaped fan and apparently are involved in rustling of the feathers. But the actual spreading Of the train can- not be explained by movements Of the tail. It appears that some other mechanism associated with the feathers Of the train is responsible for their display. Summary and Discussion NO significant differences in feather displays were noted among male Single Comb White Leghorn, bantam Rhode Island Red and Araucana chickens or among male Chrysolophus pictus and g, amherstiae. Great differences in feather dis- plays were found among males of different genera. In general, most conspicuous feather displays are local- ized in different regions Of the plumage, and homologous regions among birds may be characterized by different feather postures. Also, in a bird which is displaying, feathers in different regions Of the plumage may assume different postures. The following"is a brief summary Of the most sig— nificant points I found from my Observations on feather display. 'n -_m_ m"... 'w Li‘?‘ H 1. "Ear" tuf in the elevated a season; they are appear to move as respcnsible for p 2. The cres: iepressed and the: | 3. The COUI’. 51-1 general L; a. The fron‘ strang raising 0: rest of the beds! 33173! fea ‘ ('f O 37 1. "Ear" tufts in cock Phasianus appear to be maintained in the elevated and inclined posture throughout the breeding season; they are capable Of being raised and lowered and appear to move as a unit. The integumentary "ears" may be responsible for positioning the "ear" tufts. 2. The crest Of ChgysolOphus males appears permanently depressed and the crest Of peacocks and peahens permanently erected. 3. The courtship display Of Phasianus is characterized by a general fluffing Of all body feathers. 4. The frontal display Of Gallus is characterized by strong raising Of the hackles and strong depression Of the rest of the body feathers. Ruffling Of the hackles and Of other feathers Of the body Occurs during the head- and body- shake. 5. In ChrysolOphus, extension Of the cape feathers is the most striking feature Of the feather displays. Either side of the cape may be extended. 6. Raising and spreading Of the train to an elevated and fanned posture is the most conspicuous feather display of peacocks. Positioning Of the train apparently is not dependent upon the rectrices Of the tail. 7. Plumage-shift occurs in the lateral display Of Phasianus and ChrysolOphus, but it is most noticeable in Qhrysolophus where the yellow feathers Of the rump appear to shift toward one side of the body. B. Feathers ‘ their position ir. when the head is ".5 extended. It is possat ’2, three differen First, body :rzentation and c ‘3‘ display :: the subject. 5‘” a Ci“splay 1' «r .L d- ' aeration of t” “‘5 V‘i‘ 1". REG-me CKS c 38 8. Feathers Of the neck in all birds, regardless Of their position in display, appear to move closer together when the head is retracted and further apart when the head is extended. It is possible that the body feathers are positioned by three different, independent but interacting methods. First, body feathers may be oriented according to the orientation and position of the body. For example, the lateral display itself orients certain regions Of the plumage to the subject. The crown feathers of peafowl, if they do serve a display function, are apparently dependent upon the orientation Of the head. The positioning Of the head in cock Ring-necks close to the face Of the hen may serve to draw attention to the "ear" tufts or to the flushed facial wattles. Second, once the body is oriented further exaggeration Of the feather display appears to be accomplished by the movement Of individual feathers. Feathers may be elevated at various degrees from the body surface to produce the sleeked, relaxed, fluffed and ruffled postures, or they may mmwe forward along the longitudinal plane Of the body as in the extended feather posture Of the cape feathers in Qhrysolophus. Tips Of feathers may also move apart from one another in one plane to give a fan shape tO the group of feathers being diSplayed. These movements and postures appear to have twO things in common; that is they do not appear to be depe the movement of t tiered appears tz; Slit”. which appear ai'zage in Chrv s n; Whether the 1831:3813 aSSOCla: 'V IA“ ‘w‘ ‘ an "val-M. Sp.ay ar "fi-‘v . retires are COPE tithe skin is e NC“. 't‘ \. ‘V V u.‘ « ‘ null 0f "fga‘ ‘. . \ 33'5“}? ‘Ufl‘j D 3'39: ‘32- )1 . “at. \‘ s‘ 1F. 39 appear to be dependent upon the orientation of the body or the movement Of the skin. A third method by which display feathers may be posi- tioned appears to involve the movement or shifting Of the skin which appears to explain the shifting Of the rump plumage in ChrysOlOphus. Whether the skin is involved in the movements Of the feathers associated with extension and retraction Of the head in non-display and display behavior, and whether the feather postures are dependent or are independent Of the movement of the skin is examined further in preening birds. MOVEMENT OF THE FEATHERS AND THE SKIN DURING PREENING Birds frequently raise their feathers during preening. The different actions Of the bill and postures Of the body during preening Of particular areas of the plumage have been described for numerous birds (Simmons 1964: 280). McFarland and Baher (1968) recently attempted to determine the effects of (1) ambient temperature, (2) hunger and thirst and (3) agonistic behavior on feather posturing in the Barbary Dove, StreptOpelia decaocto, (g, risoria). They combined the fluffed and ruffled feather postures under one general cate- gory Of "feathers raised". Their results indicate that Barbary Doves raise their feathers when cold and depress them 'when hot. NO differences between body regions were observed in response to temperature, but in defensive and aggressive birds there were thy also noted t I atterpted 3::‘.‘:r see and e:-: preening in part1 :hiitens. Birds I . A ”U. ’A ?h we firha gull UV V“ ‘U “‘V“ l ---:A ‘y R- “in: §LVH a (118:: :.--- ., c m... S L .EZC‘GE 8X28 S S 'w'd‘. :2“ were occurs c' “E“! nv ' 3... yieenlng 'w . . .- ..'.e M ‘ wSt CCES'“ "‘ VA». 15 straw «n; erect ‘ Ll 40 birds there were marked and characteristic differences. They also noted that feather raising increased during preen- ing. I attempted to determine the feather postures and the occurrence and extent Of feather and skin movement during preening in partially defeathered Single Comb White Leghorn chickens. Birds were clipped and stimulated to preen accord- ing to the method previously described. Each bird was Observed individually for 20 minutes twice a day for a period Of 5 days. Direct Observations with the unaided eye were made from a distance Of 2 to 3 feet on the movements Of the skin and feathers during feather posturing. During the first several minutes prior tO preening shak- ing Of the head and body is frequent and probably serves tO remove excess water from the feathers. Ruffling Of the feathers occurs during the body and head shake. Most birds begin preening within 2-5 minutes after the water treatment. The most conspicuous form Of feather movement during preening is strong erection which positions the feathers in a ruffled posture. Usually feathers are erected before actual manipu- lation with the bill. Feathers of one area Of the body may raise even when another area is actually being preened. The occurrence Of feather ruffling during preening Of certain regions of the plumage is shown in Table 1. In general, feathers Of target areas (i.e., those areas Of the plumage actually being woe. .w. ._...t:.,.~ -m;~. . L...» .-.-...-. .-. ii ., . m it IUHE .> |LL~C.~ .w. 0.6»de TUHVMSZ @3153an Die NC v.7..whd. \A~ u :93 No.0,... 4: a. II. H .4 ~ .~ -3 «42:5...» ...- ~ Wieismua an Awe .v.u.r~..i h.-d.v-vav . .ijrvo any: 3 «ma W AJ swep.w,~.-.~ 3.U..Jn,u \ «emu-.- u-J.a.fafiv n&\fl-.3 ~ .. < u 1.... -.va. v ..~ .~.. - .~nvn.-..v...v‘~ an .n I. a their. L— nlv hymn .— FhIVrmVIul hvah d .-—~.~ kw... m u “U WAVN thvnhd n.5,“! W a nheaerJrli .H .,H .I run unflur .4. has... - sletvL-sufla.v.v«fv >H ca rv~«¢.-:fiddan r..vf~ u -GA... 4 n.~.~..<.-. 41 .HMCHEOUQMH.UQM tamup .HOBOHHH tnmflnpu.£u co>n.> tumHsmmomHoucHu.mmomuoucH .HmumESSH.E:£ .HmmHOOH.U uncoflumfl>munnd .Ommmsam mumnumomm .>OOQ can we coamou Uflomuonu ummc OOHHDOUO mafiammsmN .uxmu coma md o o o o o o o o o mma .H 0 mm o o o d m o d 0 .SO 0 o m o o O H O h o .553 o o o < o o o o o o .me o o m 0 d o o NH o o uwmmun o o o o O a < O 4 NH menu 0 O o o o m d O m o xquIUHE o o m o H o 0 mm o o xuoc .> .mmom o H m o o H m o a NH #35 o o o o o o o o o o Axum: .U mma .nu .Esn .OQm ummmun QEDM xomn xomc .mmom xom: Omcmmnm .H IOflE .> Induce .O mmoum Omawmsm mmmEOHm may mo mmmud .Hsuuo uoc UHO n o .OOHHDUUO maucmsvmumcfl n H .Uouusouo waucmsvonm u m .Omuusuoo mmm3am H d H amAwB .mcmxuflno cuczmmq mpflsz QEOU wamcflm OH mmmEsHm mnu mo chHmmH camauoo mo mcflcmmum mcflnsc OOHHMMDH Monummm mo mucmuusuoo :v-‘wlated with t feathers in those Saar“ anterior dorsal r6 Laser leg, feathe: when they are pre« The fact tha during preening a preening these fe - .-'-~ by rubbing 3:3?3’91511 gland, tray be that th I T. .. f‘ul r A . ‘1 e‘ektlono :15“ L}. . ‘ L Lue (lac-(leg D‘nng feat'r ‘‘‘‘‘‘‘‘‘ u‘, m —’ 42 manipulated with the bill) ruffle more frequently than feathers in those areas not being preened. Except for the anterior dorsal region Of the neck and the region Of the lower leg, feathers Of the target areas are always ruffled when they are preened. The fact that ruffling Of the hackles does not occur during preening appears to be related tO the method Of preening these feathers. Preening Of the hackles is per- formed by rubbing the head and dorsal park Of the neck on the uropygial gland, whereas feathers in other areas, including the lower leg, are manipulated with the bill. When the lower leg is preened the erection Of feathers is slight. It may be that the feathers of the lower leg are not capable Of full erection. We know from Observations during display that the hackles are capable Of full erection. During feather ruffling, feathers slowly raise upward and anteriorly from a relaxed position. Some rotation Of the feathers occurs particularly along the dorsolateral region Of the body. Feather erection during preening Of the back appears to start at the lower back and progresses, wave—like, anteriorly. HOwever, feather erection involves groups Of feathers. Feathers may be capable Of moving individually, but I never saw only one feather elevated and the adjacent feathers depressed. Clipping Of certain feathers allows the skin to be exposed for Observation. Apparently clipping Of the feathers hes not inhibit feathers erected tract feathers. les' noticeable l attenent of the s depressed nor cc; which feathers h: are “C'JEITQT ...e neck regi: :.E’.’5‘.ICI1 cr dep. Q : k _ '. teas and rec areas, the skin A‘IO {5 ENE; L5 "‘0 n.ved apa 353-ressing. In =.~'§eared to be “Ev-‘0 HC'W‘ever I ._:'I;‘.l 1“; r; c a O ‘ ‘ l”; St:.""~ ‘0 43 does not inhibit feather ruffling, for the stubs of clipped feathers erected in a manner similar to those Of adjacent tract feathers. However, the extent Of erection was much less noticeable in clipped feathers. I could not detect any movement Of the skin as the feathers were being elevated or depressed nor could I detect any movement Of follicles from which feathers had been plucked. Some movements of the skin and feathers were noticeable in the neck region and did not appear tO be related to elevation or depression Of the feathers. As birds extended the head and neck in order to preen certain inaccessible areas, the skin Of the neck appeared to stretch and feather shafts moved apart, anteroposteriorly, without elevating or depressing. In this instance skin and feather movements appeared to be coordinated with movements Of the head and neck. However, when the head and neck were retracted, there was a short delay before the skin Of the neck was retracted and the feather shafts drawn together. It appears that drawing Of the feathers closer together, after the head is retracted originates in the skin itself, and that movement Of the skin does not place the feather in an erected or depressed position. Birds Often depress the body feathers when being trans- ferred to and from the Observation cage. Transferring and handling Of the birds may have frightened them. Evidently strong depression Of the body feathers is a typical response i‘i‘ i L ,‘l “'1 5I ; r :fncst birds whe .tcf‘rland and Bah 1811, the feather arcund the neck. clipped along one -\ has dram inward nay pturnage is I 2' Feathers 44 Of most birds when frightened (Andrew, 1956; Marler, 1956; McFarland and Baher, 1968). However, in addition to depres- sion, the feathers Of the neck also moved closer together around the neck. In birds in which the feathers had been clipped along one side Of the neck I noted that the skin was drawn inward and tightly about the neck. Summary and Discussion 1. Except for the hackles and feathers Of the lower leg, body plumage is ruffled during preening. 2. Feathers in areas other than those preened may also ruffle, but they do so less frequently than feathers in the areas being manipulated by the bill. 3. That hackles, although capable Of ruffling, are not ruffled during preening appears to be related to the method Of preening these feathers. 4. Feathers Of the lower leg elevate slightly when preened. 5. Observations on the movement of feather shafts during erection and depression Of clipped feathers, support the hypothesis that feather raising and lowering are not depen- dent upon the movement Of the skin. 6. Movement Of the skin Of the neck, anteriorly or posteriorly, appears to cause feather shafts tO move closer together or further apart depending upon the extension or retraction Of the head. The movement Of feather shafts closer together or further apart apparently can occur with the neck I W ‘Ju’t L " feathers in the g 53:31 of feather n 4':"ay With the dour". . 7. Constrict degree of feathe: 8. Frightene differences (38?“ is“ ; ~1‘ “‘f‘ESSJ-cn- 158 With the cbserisa {"35} on C‘" ‘ c .‘l ”G“ a N!‘ h ‘Vves . ent 45 feathers in the relaxed, ruffled, or sleeked posture. This form of feather movement was also observed in the frontal display with the hackles fully erected. 7. Constriction of the skin about the neck, occurring when chickens are frightened, apparently causes the feathers to move closer together transversely without altering the degree of feather erection. 8. Frightened chickens depress the body feathers. No differences between body regions were observed in feather depression. These observations are in general agreement with the observations of Andrew (1956) on buntings, Marler (1956) on chaffinches and McFarland and Baher (1968) on doves. These limited observations substantiate my original observations of feather movement in display and suggest again that there are two basic methods of positioning the feathers: (1) Feathers which are positioned in various degrees of elevation from the body appear to be postured independently of the movement of the skin. (2) Feather movements in which feather shafts move closer together or further apart appear to be dependent upon the movement of the skin. A shifting of the plumage was not observed as feathers were elevated during preening. Based upon my observations of shifting of the plumage in the lateral display of Chrysolophus, where feathers did not appear to alter their :‘egree of elevati: Istill assume t1“.~ rte way to the p Vie I have demo: s;-e:1a1ized disc”. .e;;c:s of the bi .2 AJ‘ Qandi “v- . 3‘ "a. 51‘; werences 46 degree of elevation as they were being shifted to one side, I still assume that shifting of the plumage is related in some way to the positioning of the skin. PTERYLOSIS General I have demonstrated that the most conspicuous and specialized displays of body feathers are localized in certain regions of the body of Phasianids (e.g., anterior dorsal neck of Gallus and Chrysolophus, and the rump of £339). It may be that differences in the location of display feathers among males of different genera are related to differences in their pattern and distribution on the skin and also related to differences in the pattern and distribution of the muscula- ture associated with display and non-display feathers in homo- logous regions. In this section I have examined the relation- ship of display feathers to the pattern of pterylosis. Birds were anesthetized, the feathers removed and the feather follicles marked according to the methods previously described. I examined 10 specimens of Phasianus, 6 of Gallus, 6 of Chrysolophus and 2 of Pavo. The gross pattern of feathering is first presented for Phasianus; then comparisons are made with the other forms. Some features of the localized disPlay feathers are also described. Descriptions of the gross feather pattern are based upon the distribution of the follicles and their _,_ .1' “I gummy“, “b nan-Iv“ . ...\‘\ ’ I .4" in»?! l t I A '- r t v. we. ‘ .3 Y 0‘ . — I :‘p:~ «p5 ungugun-u J ‘F "n . ‘v 4 blue ‘H€) 5 . AV “"2" ”1" when‘ ; F ~ t»., ~« 'arc ob‘>‘.y“ ...A ' 1‘ NF;- “H‘v m3: . o t . ,u 'T‘ I 47 arrangement into rows. The terminology of Heimerdinger (1964) is used for describing follicle rows. A brief review of her terminology follows: A_£Qwr-is a group of feathers arranged either in a straight line or in an inverted V, or chevron shape, with the apex of the chevron pointing anteriorly and two arms extending posterolaterally out from the apical feather (e. g., feathers of the interscapular tract are typically arranged into chevron-shaped rows; see Figures 8 and 29). A complete row--has a central apical feather and two lateral arms of variable length. An incomplete row--lacks the central feather and may also lack the first few feathers of the arms. A gapped row--contains the central feather but lacks one or more feathers in the arms. A hash-marked row--is a single armed row of feathers. The terms "anterior", "upper" or "up" are used in my descriptions as synonyms for cephalic or cranial. "Posterior", I'lower", and "down" are used for caudal. Lateral, ventral and dorsal views showing the pterylosis of a Phasianus male are shown in Figures 6, 7 and 8. In these illustrations the pattern of follicle rows may not always be clearly evident to the reader. This may be due to (1) the crowding of the follicles together in particular regions (e.g., head), (2) the curvature of the body, or (3) the presence of intercalary contour feathers found among 71 C) .4 {he ” ,-‘ot- yr. 1‘ J "55 5‘ a ‘..~y- n4 -\ Viv. .31 ' w a. Hr)... V \ v. ‘..‘n. nun—— . o P; ,‘:V‘. u.» ”it! _-".;., I. t . -_ v-ng~ hos-~Vb ‘ 1 c P; ~ _' .— Ill [(3 I-- I "rnu um," ‘u. v“ .353 5 IA-‘ 5'. \ QV‘V 5 v n ~‘ §- . “," Uh“ '1 u (I) (V . «Veu' ‘ 1‘ .4 Vi“! 5,! . Vt. x- 48 the "normal" contour feathers which disrupts the clear pattern of follicle rows found elsehwere in the tract. Description for Phasianus A brief general description of the pterylae and apteria of Phasianus is presented. Details of the subdivisions of the capital, and the subhumeral, posthumeral, alar and caudal tracts are omitted. Pterylae Capital tract.-—This tract covers the head and has numerous subdivisions. Since the follicles of the capital tract are small, numerous and close together, only the posterior portions of this tract were marked by the method described previously. A pattern of rows is not evident to the unaided eye. Follicles of the "ears" appeared somewhat larger than adjacent follicles which may be related to the fact that "ear" tufts are slightly longer than those feathers on the rest of the head. Stiff auricular feathers are found around the external ear opening and bristles are present on the facial wattles. Dorsal cervical tract.—-This single median tract covers the anterodorsal 1/5 of the neck. Its anterior boundary is marked by the posterior border of the skull. Anteriorly it is continuous with the capital and ventral cervical tracts. Posteriorly it narrows and is continus with the interscapu— lar tract. Follicles of the dorsal cervical tract are symmetrically arranged in chevron-shaped rows with the apex "- vv‘uq‘ 4'41.'PI. "' . A: >Pe c bl: V. are the n . “F! 6;.” iii..us.. .‘ . . "E jibe m .h._ ‘ u )g""‘h A gynu L“: a p "PV 5". ‘u$.y.“ :“znu‘ ,2)“ bh‘gu.u‘ c . in" “~§":V‘\ .“*‘ t' ‘ 49 of the chevron pointing anteriorly. The apical feathers are the longest in a cheVron row (Table 2). Interscapular tract.--This single median tract is located mid-dorsally over the posterior neck and between the shoulders. It is the posterior continuation of the dorsal cervical tract and is distinguished from it by being uniformly narrow. The junction of the dorsal cervical and the interscapular tract is arbitrarily placed where the lengths of chevron rows change from being irregular to uniform (Figure 8). The posterior boundary of the inter- scapular tract is marked by the presence of an apterium which may be either devoid of follicles or with 2 to 5 follicles present mid-dorsally. Dorsal and pelvic tracts.-—These single median tracts are located on the dorsal side of the trunk. The anterior boundary of the dorsal tract is marked by the posterior limit of the interscapular apterium (Figure 8). A junction between the dorsal and pelvic tracts could not be distinguished by the pattern of follicle arrangement. The junction is arbitrarily placed with respect to a transverse line connect— ing the proximal heads of the femurs. Collectively the tracts are referred to as the dorSOpelvic tract. It is widest anteriorly and narrowest posteriorly where it termin- ates at the urOpygial pland, Follicles are arranged into chevron-shaped rows and apical feathers within a chevron row are the longest (Table 2). In general the length of feathers increases posteriorly within the tract. . I aqu h‘rJ‘ oh"! ~$Ac 4 FF ‘fifi V“ and I. u u tutu ‘P‘ d-.. "I4 '1) fly . :‘gv;' ‘urbgu. .,. ‘ ‘SV' . oubb‘.‘ ‘0 . .' NA. ‘J “’V ‘ )Q'ws; Ayuj V‘.‘ 5r.,, b“: ' rev A. .' C‘va bug . ‘ Ur 50 Ventral cervical tracts.--These are paired tracts cover— ing the ventrolateral surface of the neck. They merge with one another anteriorly to a single tract which is continuous with the capital and dorsal cervical tracts. The posterior boundary is marked by the lateral junction of the marginal coverts of the alar tract. Apical feathers of the symmetric- ally arranged chevron-shaped rows are the longest. Pectoral tracts.--These paired tracts cover the ventro- lateral surface of the breast. The tract is continuous anteriorly with the ventral cervical tract. The anterior boundary is marked by the lateral junction of the marginal coverts of the alar tract. The posterior limit, about mid— way down the trunk, is formed by a gradual diminution of row length. Follicles are typically arranged into unsymmetrical chevron-shaped rows (Table 2). The angle of each arm of a chevron row is more acute and the follicles within a row are closer together at the posterior border of the tract. Sternal tracts.--These narrow paired tracts are located on the ventral surface of the trunk, one on each side of the keel. The anterior boundary begins about half-way down the pectoral tract and appears to be separated from the pectoral tract by a small Space. Evidently this is not true for passerine birds where the anterior boundary of the sternal tract originates from the medial arms of the pectoral tract. (Heimerdinger, 1964). The sternal tract is continuous posteriorly with the abdominal tract. I have arbitrarily fl fraud dw‘lbi‘m' 1" wr‘w'; V‘u-‘uuu ‘Ffi “ A. .ru... """V‘I‘ux TM .g Lu ~ . ‘ ‘HA ,“ "‘ In M“, ‘Iyé ~ 'u,‘ 1 ‘l ll I». 1 .‘ 5.. ”A. - ~t. \ “':-‘7 . ‘ ‘ “‘w' ‘ "a u n '5‘ 4|.‘: U: l . .A‘l. . ‘ u u." h I : '. h V L. . . “‘»"1 “a.“ P ‘“*a he “1. ‘§ ‘ .n A“ . ‘§t, !,~ “ fl ‘ "“1 C k‘ Pu. ~\ ‘u .1 & '4.£r..- 5‘”: NM. "v 7“... 51 placed the junction between the two at the posterior bound- ary of the keel (Figure 7). Follicles are usually arranged in single-armed rows. Abdominal tracts.--These paired tracts are the posterior continuations of the sternal tracts and cover the ventral surface of the abdomen. The tracts merge in a mid-ventral line just anterior to the anal Opening where they terminate. Here, follicles are arranged in chevron-shaped rows. Feathers increase in length posteriorly within the tract. Lateral body tracts.--These are paired tracts covering the lateral surface of the trunk. Follicles are spaced widely apart and I could not detect a pattern of rows (Figure 6). Feathers of this tract are semiplumes. Femoral tracts.--These paired tracts cover the lateral surface of the thigh. A pattern of chevron—shaped rows is not clear. Follicle rows course anterodorsally and postero— dorsally with reference to a mid-dorsal longitudinal line. This pattern is obscured by the presence of intercalary follicles at the posterior border of the tract. Intercalary follicles are defined as follicles which are found between rows of follicles "typical“ of the tract. They are associ- ated with the borders of most tracts but are most consist~ ently present and conspicuous in the femoral tract. Crural tracts.--These are paired tracts covering the external and internal surface of the leg. Follicle rows course anterodorsally and posterodorsally with reference to 52 a mid-dorsal longitudinal line. Posterodorsally directed follicle rows of the external surface are continuous with the anterodorsal feather rows of the internal surface. Feathers are longer and closer together on the anterior and posterior borders of the tract. On the internal surface feathers are shorter and more sparsely distributed. Humeral tracts.--These paired rectangular tracts cover the dorsal anterior end of the humerus. The anterior rows of humeral feathers merge with the rows of marginal coverts. Follicle rows course dorsally with reference to a mid- dorsal longitudinal line. Feathers are close together within rows and increase in length posteriorly within the tract. Subhumeral tracts.--These paired tracts, which are not figured, cover the undersurface of the humerus and are con- cealed from view when the wing is folded. Posthumeral tracts.--Paired and located on the caudal border of the upper arm between the last secondary and the humeral tract. Not figured. Alar tracts.--These paired tracts cover the upper and undersurface of the wing and have numerous subdivisions. They are not figured. Caudal tract.--This tract includes the feathers of the tail (rectrices and their coverts) and also those feathers which are located lateral and posterior to the urOpygial gland. It is not figured. IKE SKI. nbny- ; l~~:..d . :m... .; .V.&\J*- " I ’CZHQV mun“... t“‘ n! :w at nod V‘ “ v". A. . .- ."~H :Ioh‘,‘ f ""-:.‘g r 4 —a [Ti 1 (I) P“.- .Q d g 5 it y U ‘ ‘4 In; ‘ “We 47‘. "U A V k. ‘ \p . "a 1‘ z ‘u v‘ y a ‘ "c. "L 3“ Ab- “" C . F"\‘ N f. “\"a 53 Apteria I have previously defined apteria as bare regions on the skin. However, down feathers may be present in some apteria. Included with the description of each of the following apteria is a general statement of the amount of feathering on it. Lateral cervical apteria.—-Paired and covering the side of the neck between the dorsal cervical and ventral cervical tracts. Down feathers are usually absent except anteriorly. Ventral cervical apterium.--Single and median covering the ventral surface of the neck between the right and left ventral cervical tracts. This apterium is sparsely feathered. Scapular apteria.—-Paired and located between the interscapular and humeral tracts. One or 2 longitudinal rows of down are present. Lateral pelvic apteria.--Paired and located between the pelvic and femoral tracts. Down feathers are frequent and appear randomly distributed. Lateral body apteria.--Paired. The space surrounding the lateral body tract. These apteria are sparsely feathered. Pectoral apteria.--Paired. The Space between the pectoral and sternal tracts. These apteria are sparsely feathered. Starr! H .v..1 . y. ‘ war-O F“ ..I..b “U l «.5 VHHWI 1.x.e..u.t. | . (‘vuv- Vt Us — ‘ D :15 oawar VA 3;“, g . Afls IIVU- ~ x o... s :n‘ "" ‘Uu L "9'; ~ ‘~: —-_ M- .‘Fc I "' uh. I I» ‘e._' ‘Ac ,5 . a “'1‘“ .6: r “ . A..c'elfi S‘.:H.'.‘v we t““a~ :‘4 v ' "tu ‘.h-F ‘ ‘0‘ I. v ‘_-‘N‘ 54 Sternal apterium.--Single and median. The space between right and left sternal tracts. Feathers are absent in this apterium. Crural apteria.--Paired. The space between the crural and femoral tracts. Crural apteria are sparsely feathered. Median abdominal apterium.--Single. The Space between right and left abdominal tracts. Feathers are absent in this apterium. Lateral abdominal apteria.-—Paired. The space lateral to the abdominal tracts. These apteria are sparsely feathered. Interscapular apterium.-—Single and median. One or 2 down feathers may be present mid-dorsally. The Space is located mid-dorsally at the posterior border of the inter- 'scapular tract. It is Similar to the Spinal space of Bonasa (Nitzsch and Burmeister, 1867; Trainer, 1947), Perdix, Meleagris and L0ph0phorus (Nitzsch and Burmeister, 1867) and LOphortyx (Clark, 1898), and the dorsal apterium of Colinus and Coturnix (Brewer, 1961). Comparison The gross pattern of pterylosis is similar in all forms studied and in general agrees with the descriptions of Nitzsch and Burmeister (1867) and Clark (1898). I did not detect any obvious differences among Phasianus, Gallus and ChrysolOphus in the gross pattern of the ventral, humeral, crural, femoral and lateral body tracts. I did find dif- ferences within the dorsal pterylae. These differences occurred in areas which are involved in display. 55 .Auxmu mmmv muomuu mooscflucoo N cmwBqu cowuucsh mnu mucmmmummu mafia ammo é .c3onm uoc mum muomuu Ufl>ammomuop Ucm Hmpnmu ADV paw .HmHm Amv .Hmuflmmo Adv wnu mo ucmEmmcmuum mHUHHHom may mo mHHMqu .mHmonuwum mcflzonm mDUHSUHoo mscmflmmnm mama m mo 3mH> HmumuMQII.m musmflm 56 m musmflm «on... _nc.o.m Estuaa< _~.o«uom .uaC. _nu_>.uo _~_~:u> South 3.30 “ouch _a:_Eoun< aux; .2060“. Eatoza< >com _..o.~slll «on.» Canon .m..o~a._ n.u-.» .-._aao 4‘ am a 57 .Auxmu mmmv muomuu msoscwucoo N cmm3umn coauucsn msu mucmmmummu mafia ammo mae .c3onm uoc mum muomuu HMUDMU ADV Ucm .HmHm Amy .HmuHQmU Adv mnu mo ucmEmmzmuum mHUHHHom mnu mo mHHmqu .mHmOHWHmum mcfl30£m msUHSUHoo mzsmflmmzm mama w No 3mfl> Hmuucm>ll.n musmfim 58 s musmfim «on; .mc_Eoun<.l «on; Esgm «on; 302,50 3300 Estoun< _mc.cum E:.Zo~a< I ;u_:uo _ano> you; .230 £3.02; .nc_Eoon<| .ua; Esauoml 59 Cli‘.-. 'I‘l (— 1 .ll uU‘bb. .‘sst I. .LLS..smUuQ( .fi-JQ‘UWL \ tUow-h .‘Vv.).‘uv .‘lsfivfld ill|lil 'P-cdcn'inudl‘ “install-.0 p'uatlilc || .Auxmu wmmv muomuu mooscflucoo N cmmBqu cofluocsm on“ mucmmmumwu mafia ammo one .Q3ozm uoc mum muumuu HMUDMU ADV Cam .Hmam Amv .Hmuflmmu A Hmmuoall.m musmflm 60 m wusmam Estouoc. .m_=omum.muc. “ouch .mmcoo “our? .mroEou lava; ringworm“... “ouch u_>_wa Eatwua< .muCCmo .2034 nuance 3:30 “our; _u.oE:I “uni. 3.3.0 E:_.o.a< Egan“; «one... _uo_>.oo .2300 Eatoun< u_>_on .ubwaag 61 Major differences were noted in the relative thickness of the skin and the relative length of the Specialized display feathers in homologous regions. Although Specialized dis- play feathers are present in Gallus males, their presence does not alter the basic pattern of follicle arrangement. In cock Gallus the feathers are longer and the skin is somewhat thicker in the region of the hackles than in hens. Hackles arise from the dorsal cervical and interscapular tracts. Apical feathers in a chevron row are the longest in both sexes. The gross pattern of follicle arrangement in hen ringnecks and hen chickens is similar. Phasianus cocks, as compared to cock Gallus, appear to have relatively Shorter feathers and thinner skin in homo- logous regions of the dorsal cervical and interscapular tracts. In cock Phasianus long feathers are found on the epidermal "ears" of the dorsal capital tract. These features are absent in Ring-neck hens and in the other representatives. The lateral pelvic apteria in both sexes of Phasianus are somewhat wider, relatively, than in Gallus. Chrysolophus cocks appear to have narrower dorSOpelvic tracts than ghasianus or Gallus. In Chrysologhus males the skin of the dorsal cervical tract in the area of the nape of the neck is thickened mid-dorsally into a goblet-shaped elevation about 5 to 5.5 cm wide and 13 to 16 cm long. Display feathers of the cape arise from this region. These feathers are spatulate-shaped and are much longer than those 'A'I;s I .v q nvv-A \ v... '. —‘_ rm... .. A: 2" . n I. \- an-‘ . .- ¥‘~~ ~ tn ' 1 5.1 y,“ K' 'r’ ll' ~ , ‘\-‘.4 ‘l . v, ‘-.‘ ~.:r . . “;' ‘1 “u! 1 " I . 7i. . n‘s" ‘ ~~" t \ ‘. 5.. r . “"2: ”*4 Z!’ . ‘x. n. ‘4 - Iv _ ‘\ \ 62 lateral and posterior to the thickened area which also arise from the dorsal cervical tract. Feathers of the cape are arranged in chevron-shaped rows with the apex of the chevron pointing anteriorly. Chrysolophus males differ from Gallus and Phasianus males in that the apical feather is the shortest feather in a chevron row and feathers increase in length posteriorly in chevron rows (Table 2). At the posterior border of the cape, feathers are close together transversely. Anteriorly, feathers of the cape merge with feathers of the dorsal capital tract. A central thickening of the skin also occurs in the dorsal oc— cipital region. The long filamentous crest feathers arise from this region. Females of Chrysolophus possess a reduced cape but lack the crest. The ovoid cape feathers of hens are much Shorter and the Skin is thinner than in males. Several features are distinct about the pterylosis of £339. First, the interscapular apterium which is present in Gallus, Phasianus and Chrysolophus is absent in Pavo. Second, the dorsopelvic tract is linear and of equal breadth in the region just behind the shoulders, but widens considerably over the pelvic region. The thick skin (2.5 to 3 cm) cover- ing the pelvic region corresponds to the area where the long display plumes are found. The junction of the pelvic and dorsal tracts in gayg may be distinguished by follicle size and by the presence or absence of intercalary downs which are found among the feathers of the pelvic tract but not in -.»/ .nl-_ ~ n.wv Tu]. —-..uv -I.... .. .~..~penv I-F-.~.r..fi..~an mW~.._: -~.. "J. ...-a ~ ~ .5...-»..~ ~ ».d A-.:.: a... v 7..h.-vF~ -...v..u .mv\/.~ .~.......4T...~Au.u ~...:~u.~\/.-u:~ .N.u fin.~u-~hpv.~ ..n u§.-.-I\.-. m-—»~..nu — a..T..>-~—~.v .::.~ g.» nuAv.~\/mv~hvu H. p: n vlu hd 65 mmma ma mmNfi sa mmaa ma Nmfifi Na emoa mm aa 0mm Mm OH 05m Sm mu m was em mu m Nmn ms om mm ms b New mm Sm mm mm m mmm em om mm NHH Nm Nm m mes Sm em NS Nma om mm s wmm mm mm mm fiNH mm ow m mnN me OOH mm ¢HH moa ms N «ma we Hoa om mm «Ha we H sad fie NOd mm mm mafi mm o AEHm “Ens .Hwo .uwu .UmEv .umHv .umu .oz 0H>Hmm Hmmuoa ammuoo .uomm .uumm Ua>amm ammuoa monummm o>mm mmmmmm 2w .mmflflmm massammcm .Hmuouomm u .uqu “Hafiome n .UmE “Hmuwuma u .umH “Hm0H>nmU u .Hmo umcofiumfl>mHQQ< .msumumHHU 0>mm 0cm mDUUHm mDSQOHommHSU .mDHHmm madamo .mDUH30HOU mDCMHmmzm mama mo muumuu mDOHHm> Eoum .Eum cou>mzu m CH A.EE aflv mumnummm m>Husmecoo Hmsofl>flpcfl m0 mnumcmq N Hflmdfi ,Qg Eran.» I Y i o A . a- on: L\- u ”A'- .,. H on .y. "‘ Ora I'v hAA: 1336 ' Q “‘ Pr» V. ”v s ‘9‘ ~. L..“ .Fa “ A I”: Veal (D (D t J. a” . 1y i‘ “‘3 « N f 5 . ‘L I 3 . C «35> t' ‘V;. F 5.. "u 64 the dorsal tract (Figure 50). Intercalary downs have been previously described for £239 (Sager, 1955). In the pelvic tract of Egyg_the apical feather is not the longest feather in a chevron row and feathers increase in length posteriorly in a chevron arm (Table 2). In this respect the feathers of the pelvic tract of £319 are similar to the feathers of the cape in Chrysolophus. This appears to be related to the fan-shaped form of the feather displays of both representatives. In peahens the arrangement of follicles in the pelvic tract is Similar to that in peacocks but in peahens the thickness of the Skin and length of the feathers of the train are greatly reduced. Both sexes possess permanently erected crest feathers arising from the dorsal capital tract cover- ing the frontal bone. The skin of this region is also thick- ened. Summary 1. No significant differences were found in the gross pattern of follicle arrangement of the ventral, humeral, crural, femoral or lateral body tracts among males in Gallus, ChrySOIOphus or Phasianus. 2. An interscapular apterium is present in Gallus, Phasianus and Chrysolophus but is absent in Pavo. 5. The pelvic tract of Pavo is distinctly different from those of the other representatives studied. It is characterized by being wider posteriorly than anteriorly and Sn... J I . -‘ UV m, H- a. ‘( ) LA) I ' \ 'L C 'I‘ .‘I .. , . ’5 .9 A,- . t; - t...; ‘ E I. 59 s... A‘ {Q but a”. u.- . 4"“ s )1 I {)4 65 by having small intercalary down follicles interspersed among the follicles of the train feathers. The anterior limit of intercalary downs can be used to delimit the dorsal from the pelvic tract. 4. The presence of enlarged follicles of display feathers does not alter the basic pattern of follicle arrangement. 5. A thickened skin is associated with the presence of enlarged follicles of display feathers. Thickening of the skin in feathered areas may be associated with the development of the smooth muscles found within the dermis. 6. Hackles arise from the dorsal cervical and inter- scapular tracts in Gallus, cape feathers from a restricted region of the dorsal cervical tract in ChrysolOphus. 7. In general, the lengths of feathers within a tract decrease posteriorly along the arm of a chevron row. Thus, apical feathers of a chevron row are usually the longest within the row. Exceptions to this are found in the cape of Chrysolophus and the train of gayg where feather length increases posteriorly along the arm of a chevron row and the apical feather is the Shortest. This appears to be related to the displays of these feathers. Both the cape and the train are fan-shaped when fully displayed. 8. Generally, the lengths of feathers increase poster- iorly within feather tracts and from head to tail in continuous tracts. This pattern may be modified in areas ‘where there are display feathers. In males display feathers :f 53:. w. (“urn I. ‘ a“ \vns‘ —‘ ”at r‘ih bva‘. ..v C I 1 V nynauf Quick-Id, “ .‘_ . K. ' U A..Kn: I . u I "a a); 5+ \ ‘ A a "P.~‘ 5‘. 1’- VB r) i ‘ .fl' 66 of some particular tracts (e.g., dorsal cervical of Gallus and Chrysolophus) are longer than those feathers of adjacent posterior tracts. DERMAL MUSCLES Introduction and Review of the Literature Dermal muscles (= cutaneous, subcutaneous muscles) are striated muscles which arise from a part of the skeleton or a large body muscle and insert on the undersurface of the skin. The purposes of this section are to describe the gross structure of the striated muscles associated with the skin, to record similarities and differences among several galliform genera, and to make a qualitative evaluation of the differences noted in order to determine their functional implications in feather display. Hopefully, this work will help to stabilize the muscle nomenclature and serve as a basis for detailed comparisons yet to be made for other orders and families of birds. I have selected Phasianus colchicus as a type for comparison with the other forms. Jacquemin (1856) was apparently the first to describe the striated dermal muscles of the Skin. However, his account is brief and inadequate. Owen (1842) presented the first detailed account of the dermal muscles for a single species, a kiwi (Apteryx australis). He recognized 10 distinct and separate muscles, 6 of which were associated with the skin of the neck. 67 Of these muscles I have retained the terminology only of his M. constrictor colli. Viallane (1878) described 2 skin muscles, M. temporo- alaire (= cranial portion of M. cucullaris pars cranialis) and M. frontoiliac (= M. latissimus dorsi pars dorsocutan- eus) responsible for elevating the neck feathers in the display of the Superb-bird-of-paradise (LOphorina superba). Helm (1884; 1886) examined and described the relation- ships of 15 dermal muscles to the feather tracts in several orders of birds. For the most part his terminology follows that of Owen (1842). He illustrated 8 of these muscles for a "type" waterfowl. Ffirbringer (1888; 1902) was the first to undertake a broad and exhaustive comparative study of the musculature in different families and orders and to bring together in one work the complete synonymy of names used for various muscles. He also was the first to recognize that many dermal muscles which occupy the greater portion of the neck, and which were previously described as separate muscles, con- formed to one general plan. He considered these muscles as part of M. cucullaris. The only muscle superficial to it is his M. sphincter colli (= constrictor colli). Accord— ing to Ffirbringer, M. cucullaris has two main divisions. The Kopftheil (pars cranialis) attaches to the skull, Spinal ‘pterylae, clavicle, sternum, and prOpatagium. The cephalic portion of Ffirbringer's Kopftheil is considered by George and ‘ | ~-M. guyuki ‘9“~Fn w. 1;, _, '11 , :1va \‘.IA "1 '__. . (* f p: 1 r (T! 68 Berger (1965: 272) to be M. complexus, a muscle of the axial skeleton, rather than a dermal muscle. M. complexus is the same as the hatching muscle of Fisher (Fisher, 1958; 1961; 1962). The Halstheil (pars cervicalis) of Furbringer's cucullaris arises from the neck and is inserted near or in common with pars cranialis. Ffirbringer also noted that many cutaneous muscles corres- ponded to dermal slips of already well known appendicular muscles. In fact he suggested that the posterior portion of his M. cucullaris dorso-cutaneus (1888: 502). which he found in some birds, be considered as a dermal component of M. latissimus dorsi (= M. lattissimus dorsi pars dorsocutaneus, 1888: 829). In my descriptions of the dermal muscles of the neck I have adoptdd Ffirbringer's muscle terminology of the cucullaris system. I found Ffirbringer's account of the dermal muscles to be by far the most complete and extensive in the literature. Shufeldt (1890) was the first anatomist, so far as I know, to study in detail the complete myology of any bird. But numerous errors in his descriptions and findings in the myology of the Raven (Corvus corax sinuatus) have been reported by subsequent investigators (Engels, 1958; Hudson and Lanzillotti, 1955). For this reason I have not used Shufeldt's terminology for the dermal muscles nor have I relied on his descriptions of them. However, his work should not be com— pletely ignored as George and Berger suggest (1966: 225), A A' CA? J. .90 up 1.! (J . U) Q q _ ‘H $5..)vl O UiU‘ . 'IIAA; N- it.» u ~ ":t\ vu,‘ ~. F. (I! 0A.. N.- i.“ ll} 69 for Shufeldt frequently included the synonymies of Gadow and Selenka (1891) in his footnotes. With reference to the dermal muscles, Shufeldt compared his terminology to that of Ffirbringer, Gadow and Selenka, and Owen. However, he still chose to devise his own nomenclature of the 15 dermal muscles he found rather than to adopt Ffirbringer and Gadow's concept of the composite M. cucullaris and to follow their classifi— cation of the cutaneous components of body muscles. Gadow and Selenka's monograph (1891), like Ffirbringer's, is also a comprehensive study on the comparative myology of birds. Gadow and Selenka provide an extensive list of synonymies for the dermal muscles but omit those of Helm and Shufeldt. They divided M. cucullaris into superficial, deep and propatagial components. Beddard (1898) surveyed the myology of representatives of many orders and families of birds reported by previous workers. He followed the terminology of Ffirbringer for his descriptions of the dermal muscles. Fisher and Goodman (1955) undertook an extensive study of the myology of the WhOOping Crane (Grus americana). They divided M. cucullaris into a caput or capitis part (Kopftheil of Ffirbringer) and a hals or cervical part. They also described M. dermotemporalis (Shufeldt) which corresponds to my M. cucullaris pars cranialis as it arises from the skull. Fisher and Goodman's caput portion of M. cucullaris is M. complexus of Gadow and Selenka (1891), Boas (1929), Davids (1955), Zusi (1962), and Lucas and Stettenheim (1965). __ _" v ‘\J 1 K J... I 'fl PM . .bvvr‘ - is b- . fl'\r- Iv... LG" ‘5‘. IS“ (.') ()1 r 1. 70 In a recent synOpsis of the myology of birds George and Berger (1966: 270-272, 295, 506, 517) reviewed the homologies of the striated dermal muscles of Shufeldt, Ffirbringer, and Gadow and Selenka. They stated that there is no evidence for the actual existence of Shufeldt's Mm. dermo-frontalis, circumconcha and dermo-spinalis, that M. cucullaris is not a true muscle of the axial skeleton and that M. complexus is not a part of M. cucullaris but rather a true muscle of the axial skeleton. They retained Shufeldt's terminology of M. dermotemporalis in their descriptions of the cranial attachment of M. cucullaris in the Red-winged Blackbird (Agelaius phoeniceus) and Rivoli's Hummingbird (Eugenes fulgens). They also described 4 possible dermal components of M. pectoralis pars thoracicus, 5 of which corresponded to Gadow and Selenka's (1891) pars abdominalis. Materials and Methods Specimens for dissection were prepared as described in the Methods section. Complete dissections were made on both Sides in the following: Total Males Females Gallus gallus Single Comb White Leghorn Rhode Island Red Araucana Phasianus colchicus Chrysolgphus pictus Chrysolophus amherstiae Pavo cristatus mpemmmm Hpmmpem Hopmpem 1’..-" :..a, :1"? ”W.“ : q,“ I... ”‘1’. 71 In order to ascertain whether striated muscles were attached to the follicles I often examined at 450x teased skin tissue stained with hematoxylin. In determining the length of dermal muscle slips I nuaasured from the origin to the insertion end on the skin. Iriformation as to the innervation of the dermal muscles has tween obtained from numerous sources (Ffirbringer, 1888; Gadow arnd Selenka, 1891; Edgeworth, 1955; Goodman and Fisher, 1962) . Abbreviations Abbreviations for the dermal muscles are given under time description of each muscle and in the figures. The ft>llowing are additional abbreviations: adb. = abdominal, abdominis m. — musculus ant. = anterior marg. = marginal anterovent. = anteroventral mm. = musculi apt. = apterium, apteria n. = nerve cap. = capital 0p. = opening cer. = cervical pect. = pectoral cov. = coverts post. = posterior d. = dorsal posterovent = posteroventral ex. = external reg. = region ext. = externus sar. = sartorius hum. = humeral sp. = Space interscap. = interscapular tr. = tract 1. = left v. = ventral 72 REVIEW OF THE DERMAL MUSCLES M. constrictor colli (Con. colli) (gygg) M. constrictor colli, Owen, 1842: 22. Helm, 1884; 526; 1886: 298. Edgeworth, 1955: 109. Fisher and Goodman, 1955: 27. Goodman and Fisher, 1962: 114. M. Sphincter colli, Ffirbringer, 1888: 505. Beddard, 1890: 80. Oberflachliche Lage M. cucullaris, no. 64 I, Gadow and Selenka, 1891: 214-216, 506. Description for Phasianus (Figure 9).—-M. constrictor <2c>1li is the most superficial muscle of the neck. It takes its origin from the ventral median raphe. The fibers encircle tiles neck transversely, are continuous with one another mid- llicles of the cape feathers. The muscle surrounds the vvrnole of the neck in Apteryx (Owen, 1842: 22) and lies be— ‘tvveen the posterior ends of the mandibles and the 6th and '7tih vertebrae in Grus (Fisher and Goodman, 1955: 27). The Intascle was not described for any of the gallinaceous birds 13)? Ffirbringer (1888) nor for the Raven by Shufeldt (1890). M. M. M. M. THE CUCULLARIS COMPLEX (Ffirbringer) M, cucullaris pars cranialis (Cuc. cran.) sterno—maxillaris, Owen, 1842: 25. temporo-alaire, Viallane, 1878: 6-12. subcutaneus colli, Helm, 1884: 555; 1886: 298. furculo-cephalicus, Helm, 1884: 557; no. 10, 1886: 559. Part M. cucullaris, Kopftheil (Pars cranialis), M. Ffirbringer, 1888: 504. Beddard, 1898: 80. Part of the Tiefere Lage, M. cucullaris, no. 64, Gadow and Selenka, 1891: 214. Not the capitus portion .(caput part) of Fisher and Goodman, 1955: 10, or Goodman and Fisher, 1964: 116. dermo-temporalis, no. 5, Shufeldt, 1890: 5,6. Fisher and Goodman, 1955: 9. Goodman and Fisher, 1964: 115. 7/.- ... I. Hy 74 Pars cranialis of M. cranio-cervicalis, Edgeworth, 1955: 145. Dermal component of M. pectoralis, no. 12 (4), George and Berger, 1965: 506. Description for Phasianus (Figures 9, 10, 11a and :LEZa).-—Whereas the fibers of M. constrictor colli transverse ‘tlme neck, the fibers of M. cucullaris pars cranialis, which are deep to it, are longitudinal and run the entire length c>if the neck. Pars cranialis arises fleshy, cranially, from the region of the squamosal bone, just dorsal and anterior tr) the external ear fossa (Figure 11a). At this point pars cranialis (M. dermo-temporalis, Shufeldt, 1890) is about 6 Inj.1limeters wide. Once free of the Skull it widens out posteriorly to a flat Sheet which overlies M. complexus and the superficial muscles of the neck. It receives a few iiilsers from the auricular cartilage and from the posterior Part of M. constrictor colli. The major portion of pars <=rwanialis meets its partner mid-dorsally, but does not ccDrinect with it. It then courses posterolaterally and 'Verrtrally to merge with the like muscle from the Opposite SiJSEB as a single broad muscle sheet overlying the cr0p (FEiSrure 10). It eventually narrows and attaches to the ligament (posteroventral portion of Membrana sterno—coraco— Clavicularis, Gadow and Selenka, 1891; Woolfenden, 1961: 124) Which unites the hypocleidium and the sternal Spine, and to faSCIia covering M. pectoralis thoracia (Figure 12a). cl!) .nh 75 At about mid—length of the neck some of the fibers fan out laterally and terminate at the anterior end of the thoracic region which is marked by the under marginal coverts of the prepatagium (Figure 10). Here pars cranialis is most firmly bound to the overlying skin and it is difficult to separate the two. The muscle is also thinnest at this point. The posterior portion of pars cranialis (= dermal com- ponent of M. pectoralis, George and Berger, 1965: 506) which covers the cr0p is not intimately bound to the skin, except mid-ventrally in a transverse line drawn between the under marginal coverts of the prepatagium. M. cucullaris pars cranialis does not conform directly to the pattern of pterylosis. It passes diagonally and posterolaterally beneath the dorsal cervical tract and lateral cervical apterium and then courses ventrally to the anterior cervico—thoracic region. In the ventral cervico- thoracic region, fibers from both dorsal fasciculi form a ventral muscle Sheet which at its widest extent lies beneath the ventral cervical apterium, between the medial (innermost) 7 follicles of the right and left pectoral tracts. The maximum width of the dorsal faciculi ranges from 58 to 45 millimeters, the single ventral fasciculus cover- ing the crop, 48 to 52 millimeters, and the attachment of the latter to the sternal region 8 to 15 millimeters. Pars cranialis is relatively thicker than M. constrictor colli, and its length corresponds to the length of the neck. 5 -24-‘ , I t _ I magma: 76 Comparison.--The cranial attachment of M. cucullaris pars cranialis is relatively thicker in male Gallus and Chrysolophus, especially where it passes beneath the fol— licles of the display feathers found on the dorsal cervical tract (hackles of Gallus, cape feathers of ChrysolOphus). However, the shape, origin, and course of the muscle does not differ significantly from that of Phasianus. The posterior portion of pars cranialis covering the crOp is similar in all the forms I examined. M, cucullaris pars dorsocutaneus Anterior part of M. fronto-iliaque, Viallane, 1878: 6-17. M. cucullaris dorso-cutaneus, no. Ib, Ffirbringer, 1888: 502. M. dermo—dorsalis, no. 4, Shufeldt, 1890: 6. This paired dorsal slip of M. cucullaris pars cranialis is present in Chrysolophus and £339 and absent in Gallus and Phasianus. Pars dorsocutaneus leaves pars cranialis at its most dorsal aspect, as the latter turns laterally and ventrally. Pars dorsocutaneus, about 2 millimeters wide in both Chrysolophus and £332, courses directly caudally, maintaining a uniform width until it reaches its most poster- ior extent where it diverges slightly to insert by thin fascia onto the integument. The caudal connection to the skin is just cranial to the anteriormost attachment of the cervical component of M. cucullaris pars cervicalis in the we“: "'_""‘""‘T".fi"—«‘V . . ._ . H. . 77 anterior interscapular region of ChrysolOphus, and just anterior to the caudalmost attachment of pars cervicalis in Egyg (although not diagrammed, refer to Figure 9). Pars dorsocutaneus is not firmly bound to the skin along its length, except where it terminates caudally, nor does it connect with M. constrictor colli or M. cucullaris pars cervicalis. In relation to pterylosis the caudal attachment of pars dorsocutaneus underlies the two outermost follicles (sf the interscapular tract. In a more extensive condition guars dorsocutaneus may meet with M. latissimus dorsocutaneus (63.9., Alca, Uria, most Limicolae) or fuse to a common tendon Mtith it which passes to the pelvis (e.g., Meiglystes, and tile majority of the passerine birds-~Ffirbringer, 1888: 505). M, cucullaris pars propatagialis M. temporo-alaire, Viallane, 1878: 6—17. M. tensor cutis brachialis anterioris, Helm, 1886: 299. M. cucullaris prOpatagialis, no. Ic, Ffirbringer, 1888: 502. Pars prOpatagialis M. cucullaris, no. 64 III, Gadow and Selenka, 1891: 216. M. dermo—tensor patagii, no. 6, Shufeldt, 1890: 4, 7. This muscle, which splits off laterally from M. cucullaris ENirS cranialis in the cervico-thoracic region and goes to the IPrOpatagium, was not present in Phasianus, Gallus, SfigysolOphus or Pavo. V ‘17- ~' -‘ 7w 78 M, cucullaris pars omocutaneus Perhaps M. humero-Spinalis, no. 15, Helm, 1886: 541. M. cucullaris omo-cutaneus, no. Id, Ffirbringer, 1888: 505. Ffirbringer gave this name to a muscle he found in Apteryx, Columbidae, Anatidae, many Limicolae and a few Galli. It departs from M. cucullaris pars cranialis and inserts onto the integument of the humeral tract (Ffirbringer, 1888: 507). I did not find pars omocutaneus in Phasianus, (Sallus, ChrysolOphus or Pavo. M, cucullaris pars metapatagialis M. cucullaris metapatagialis, Ffirbringer, 1888: 502. Pars metapatagialis, a slip of pars cranialis, which sgoes to the metapatagium and was described for Uria (Ffirbringer, 1888: 505), was not present in any of the forms I examined . M, cucullaris pars cervicalis (Cuc. cer.) M. dermo-transversalis, Owen, 1842: 25. Helm, 1884: 526, 549: no. 5, 1886: 500. Perhaps M. sterno-cervicalis, Owen, 1842: 25. M. dermo-furcularis, no. 9, Helm, 1886: 559. M. dermo-spinalis, Owen, 1842: 24. M. cucullaris, Halstheil (Pars cervicalis), Ffirbringer, 1888: 506. Beddard, 1898: 80. Part of the Tiefere Lage, M. cucullaris, no. 64, Gadow and Selenka, I‘I‘IHWILUHHM am. . .7. :v w. 79 1891: 214. HalS part of M. cucullaris, Fisher and Goodman, 1955: 49. M. dermo-cleido dorsalis, no. 7, Shufeldt, 1890: 8. Pars cervicalis of M. cranio-cervicalis, Edgeworth, 1955: 146. Description for Phasianus (Figures 9, 11b, and 12a).-— . -' .‘0 b4. cucullaris pars cervicalis in Phasianus consists of two sveparate components, one which arises from the lateral sur- fiace of the neck, the other from the dorsal medial border (sz the clavicle. Cervical component.--This muscle (= M. dermo-transver- salis, Owen, 1842: 25; Helm, 1886: 500) consists of 5 to 5 ‘tlain slips, each about 5 millimeters wide. They originate Ixy'a thin aponeurosis from the lateral surface of cervical vertebrae 7 to 11 where the ventral root of each cervical :slpinal nerve emerges from between Mm. longus colli ventralis axud intertransversarii (Figure 11b). The slips, once free of the neck, course obliquely EKDsterodorsally beneath the lateral cervical apterium and tTMen diverge Slightly to insert by thin fascia onto the irI‘tegument beneath the lateral follicles of the interscapular trfact (Figure 9) . Clavicular component.--This paired muscle is termed bq,, dermo-cleido dorsalis by Shufeldt and M. dermo-furcularis 135’ Helm. It arises by fascia from the anteromedial surface Kit I; 80 of the dorsal one-fifth of the clavicle (Figures 11b, 12a, and 12b). The muscle then courses dorsally and postero— medially beneath the lateral cervical apterium to insert by thin fascia onto the integument beneath the lateral follicles of the posterior region of the interscapular tract. The insertion is caudal to the most posterior slip of the cervical component of pars cervicalis and just anterior to the in- sertion of M. latissimus dorsi pars dorsocutaneus (Figure 9). Comparison.--Both the cervical and Clavicular components of M. cucullaris pars cervicalis are well deve10ped and similar in Chrysolophus, Gallus, and £329. The slips from the lateral surface of the neck generally number 4 or 5 and may vary as to the cervical vertebrae from which they arise. The cervical slips arise most frequently from cervical verte— brae 7 to 11, less often from 8 to 12, and 6 to 10. For the purpose of this investigation I do not consider these dif- ferences to be Significant. The cervical component arises from the inferior trans- verse processes of the 6th to the 12th cervical vertebrae inclusive in Apteryx (Owen, 1842: 24), from the 7th to the 11th in Gallus, and from the 4th to the 11th in Nothura maculosa (Helm, 1884: 549). According to Ffirbringer (1888: 506) pars cervicalis can show many grades of development in its attachment to the spinous processes of the cervical vertebrae, to the skin, and to the clavicle. In cases of considerable deve10pment 7m “‘9‘?” . 81 pars cervicalis extends as a broad Sheet in direct connection with pars cranialis over the distal five-sixths to one-half of the neck (e.g., one—half in Meleagris). In the case of little deve10pment it is represented by a thin bundle at the end of the trunk (e.g., Argus). Pars cervicalis is strongly deve10ped in Mags (Helm, 1886: 541) and QEEE (Fisher and Goodman, 1955: 49). Fisher and Goodman described pars cervicalis (= their hals part of M. cucullaris) as a muscle, some 9 centimeters wide, which overlies the anterior part of the cervico-thoracic region and extends to the shoulder. In §£E§ it arises from the neural crests of vertebrae 18, 17, and 16 and inserts on the scapu- lar head, furculum, and the Clavicular air sac. There is no mention of its attachment to the overlying skin and its relationship to the feather tracts. I did not find any attachment to the neural spines in the forms I examined. Innervation.--The anteriormost region of M. cucullaris pars cranialis is innervated by branches of N. hypoglosso- accessorius, accessorius externus and the vagoaccessorius; the remaining part of M. cucullaris pars cervicalis by numer- ous branches from cervical nerves and nerves from the brachial plexus (Ffirbringer, 1888: 507; Edgeworth, 1955: 146; Goodman and Fisher, 1962: 115). __ -1. _._.,..._...I r firm 82 DERMAL COMPONENTS pg M. LATISSIMUS DORSI (Ffirbringer) M, latissimus dorsi pars dorsocutaneus (Lat. g, gg,) M. dermo-spinalis, Owen, 1842: 24. Helm, 1884: 526; 1886: 557. Posterior part of M. fronto—iliaque, Viallane, 1878: 6-12. Posterior part of M. cucullaris dorso-cutaneus, No. Ib, Ffirbringer, 1888: 502. M. Latissimus dorso-cutaneus, Ffirbringer, 1888: 829. M. dermo-iliacus, Shufeldt, 1890: 12. M. latissimus dorsi dorso-cutaneus, Beddard, 1898: 79. Gadow and Selenka, 1891: 250. M. latissimus dorsi pars dorsocutaneus, George and Berger, 1966: 294. Description for Phasianus (Figures 9 and 12b).-- M. latissimus dorsi pars dorsocutaneus is a thin, fleshy muscle, about 2 millimeters wide and 65 millimeters long, which arises from the superficial surface of the posterior end of M. latissimus dorsi pars posterior and from the neural Spines of the last thoracic vertebra. At its origin pars dorsocutaneus fuses with the like muscle on the Opposite side and partially covers M. latissimus dorsi pars meta— patagialis (Figure 12b). The thin band runs diagonally anterolaterally beneath the dorsal feather tract and diverges slightly to insert by fascia onto the integument beneath the T5 I .41.! .. ‘m ' ' \ I ”3.1- ~ 85 lateralmost follicles Of the interscapular tract just caudal to the insertion of the Clavicular component of M. cucullaris ‘pars cervicalis (Figure 9). Medial fibers Of pars dorso- <:utaneus course superficial to fibers of the latter without connecting with it. Pars dorsocutaneus is most firmly bound to the skin at its anterior termination. . --.~.~r nut-$1 Innervation.--By a branch Of N. latissimus dorsi (Ffirbringer, 1888: 568, 572) . ‘ “Mil . k ) Comparison.—-Pars dorsocutaneus is equally deve10ped arufl.similar in ChrySOIOphus, Gallus and £939, Furbringer (11388: 566) stated that in galliform birds pars dorsocutaneus Sruows all possible gradations in deve10pment (e.g., weak in §i£313§), in separation from M. latissimus dorsi pars meta— IPErtagialis (e.g., incomplete in Argus, Numida), and in union VVi;th M. cucullaris pars dorsocutaneus (e.g., united in rI'Eetraonidae). In ChrySOlOphus and £939 I found the insertions C315 M. cucullaris pars dorsocutaneus and M. latissimus dorsi IPEIrS dorsocutaneus to be separated by the insertion of the cIlavicular slip Of M. cucullaris pars cervicalis. Hudson and Lanzillotti (1964) did not describe pars ciorsocutaneus for Gallus, Phasianus, or £939. The posterior IPCDITtion of their unlabeled muscle in Gallus (1964, Figure 1, F>- 94) appears to correspond to my pars dorsocutaneus, their Cranial portion to my Clavicular component of M. cucullaris pars cervicalis. They figured a uniform band Of muscle 84 which courses from the origin of M. lattissimus dorsi pars metapatagialis and passes cranially over the shoulder. M, latissimus dorsi pars metapgtagialis (Lat. 9, 999.) M. dermo-iliacus, Owen, 1842: 24. No. 6, Helm, 1886: 557. M. latissimus dorsi pars metapatagialis, Ffirbringer, 1888: 565. NO. 68 III, Gadow and Selenka, 1891: 228. George and Berger, 1966: 288. M. latissimus dorsi metapatagialis, Beddard, 1898: 79. Hudson, 1955: 7. Hudson and Lanzillotti, 1964: 8. Lucas and Stettenheim, 1965: 14. Description for Phasianus (Figures 9 and 12b).--This dermal slip, 55 millimeters long and 5 millimeters wide, arises from the superficial surface of M. latissimus dorsi pars posterior and the neural spines of the thoracic verte- brae. Its origin is deep and slightly posterior to the origin of M. latissimus dorsi pars dorsocutaneus (Figure 12b). Pars metapatagialis is about 2 millimeters wide at its origin. The uniform belly passes obliquely anterolaterally beneath the scapular apterium and narrows to a small tendon which unites with the tendon of M. serratus superficialis pars metapatagialis. The two muscles insert onto the metapatagial membrane just caudal to the posteriormost follicles of the humeral tract (Figure 9). Pars metapatagialis is not firmly bound to the integument except at its insertion (fold of the metapatagium). f _V.. ) _. , 4 . firm 85 Innervation.--By a branch from N. latissimus dorsi (Furbringer, 1888: 568, 572). Comparison.—-Pars metapatagialis is equally developed in ChrygoloLhus, Gallus and £939 where its origin, course, and insertion are very similar to those of Phasianus. An accessory Slip arising from the lateral surface of pars metapatagialis was present, unilaterally, in one specimen of Gallus (Single Comb White Leghorn). This slip, about 2 millimeters wide, passed directly ventrally over the surface of M. serratus superficialis pars metapatagialis to attach to the skin just anterior to the insertion of M- pectoralis thoracica pars subcutaneus thoracicus. Both pars metapatagialis and pars dorsocutaneus are about the same width in Phasianus, ChrysolOphus, Gallus and Pifiv‘o. Pars metapatagialis arises from the last thoracic vertebra, fascia of the linea alba, and the first presacral Vertebra (synsacrum) in Meleagris gallOpavo, Lyrurus tetrix (Tetrao tetrix) and Crax nigra (Crax alector) (F'urbringer, 1888: 571) . The muscle is broad but weak in Numida and Lcryllium; broad and somewhat stronger in Opisthocomus (Hudson and Lanzillotti, 1964: 8) . M. latissimus dorsi-omocutaneus (Lat. 9, omocut.) This muscle, located between Mm. latissimus dorsi pars CiOrsocutaneus and metapatagialis in Argus and Numida (Ffirbringer, 1888: 566) , is not present in Phasianus, C3&ysolgahus, Gallus or Pavo. :7 A u I. h!- H\U 86 DERMAL COMPONENTS Q§_M, SERRATUS §UPERFT€IALIS (Ffirbringer) M. serratus superficialis pars metapatagialis (Ser. 9, 999.) M. dermo-costalis, Owen, 1842: 24. M. tensor cutis brachialis posterioris, no. 7, Helm, 1866: 558. M. serratus superficialis metapatagialis, Ffirbringer, 1888: 578. No. 66b, Gadow and Selenka, 1891: 221. Beddard, 1898: 81. Hudson, 1955: 11. Hudson and Lanzillotti, 1964: 11. Lucas and Stettenhaim, 1965: 14. M. dermo-ulnaris, no. 11, Shufeldt, 1890. Not of Owen, 1842: 24. M. serratus metapatagialis, Berger, 1966: 299. Description for Phasianus (Figures 9 and 12b).-—Pars metapatagialis, 60 millimeters long, typically arises from the lateral surface of the vertebral member Of the third thoracic rib, just ventral to the uncinate process, and sometimes from the third to the fourth thoracic ribs inclu- sive. In the latter case the muscle also originates from an aponeurosis between the ribs. The two fasciculi fuse to form a common belly some 4 to 6 millimeters wide. The muscle passes forward and upward beneath the lateral body apterium, narrows to about 2 millimeters, and inserts as a cord-like tendon in common with the tendon of M. latissimus dorsi metapatagialis onto the metapatagial membrane. M. serratus __- v-h. _.—“ * —~ "Tm; =7 .1 v 87 superficialis pars metapatagialis is stronger and more cord- like than Mm. latissimus dorsi pars dorsocutaneus and pars metapatagialis. It is not firmly bound to the Skin except at its insertion. Innervation.--By N. serratus superficialis metapatagialis which branches off from N. serratus superficialis posterior r} (Ffirbringer, 1888: 581). as- Comparison.——Very similar in all the forms I examined. The most frequent origin is from the third thoracic rib just ventral to the uncinate process. Variation in the origin of pars metapatagialis is given for numerous galliform genera by HUdson and Lanzillotti (1964: 12). M, serratus superficialis pars dorsocutaneus M. serratus superficialis dorso—cutaneus, Ffirbringer, 1888: 578. Ffirbringer (1888:581) gave this name to an additional muscle he found in Apteryx which courses dorsally to insert onto the undersurface of the skin covering the scapula. I did not find it in Phasianus, Gallus, Chrysolpphus or Pavo. DERMAL COMPONENTS _QE M. PECTORALIS M, pectoralis thoracica pars subcutaneus thoracicus (Pect. ;c_. sub. :9.) Anterior part of M. dermo-humeralis, Owen, 1842: 24. No. 12, Shufeldt, 1890: 15. 88 M. subcutaneus thoracicus, no. 4, Helm, 1886: 501. M. pectoralis abdominalis pars anterior, Ffirbringer, 1888: 450. Beddard, 1898: 79. Hudson and Lanzillotti, 1964: 14. M. pectoralis abdominalis pars subcutaneus thoracicus, no. 75 III, Gadow and Selenka, 1891: 242. E‘ Dermal component of M. pectoralis, no. 12 (2), George ' and Berger, 1966: 506. Y Description for Phasianus (Figures 10 and 12a) .-- - r M. pectoralis thoracica pars subcutaneus thoracicus is a dermal muscle covering the lateral thoracic region. It arises by a narrow tendon and a strong sheet Of fascia bridg- ing the insertion of M. pectoralis pars thoracica. The wide but thin belly courses posteriorly and ventrally to diverge and insert by fascia onto the integument beneath the outer- most follicles of the posterior seven to ten feather rows of the pectoral tract (Figure 10). Pars subcutaneus thoracicus is firmly bound to the skin beneath the posterior boundary of the lateral body tract and the lateral body apterium which it crosses. Innervation.--By a branch Of N. pectoralis pars thoricica (= N. pectoralis abdominalis; Ffirbringer, 1888: 455). Comparison.--The major portion Of M. pectoralis thoracica pars subcutaneus thoracicus is similar in Gallus, Chrysolophus, and Pavo. However, I found one abberation in Gallus. 89 Sometimes fibers of pars subcutaneus thoracicus continue directly from the pectoral tract to the integument beneath several outer follicles of the sternal tract (unilateral in one specimen, bilateral in another). M, pectoralis abdominalis metapatagialis (Ffirbringer) The muscle which departs from pars subcutaneus thoracicus and goes to the metapatagium in some birds (Ffirbringer, 1888: 455; 1902: 440) was not present in the ifiorms I examined. This muscle of Furbringer appears to cxarrespond to a minute slip which Hudson and Lanzillotti ftrund in most American quails they examined. They stated tliat it passes from the insertion Of pars subcutaneus trnoracicus toward the insertiOn of M. latissimus dorsi pars Inertapatagialis (Hudson and Lanzillotti, 1964: 14). M, pectoralis thoracica pars subcutaneus abdominalis (2.2::- 211: EEP: 229,-) Posterior part, M. dermO-humeralis, Owen, 1842: 24. M. pectoralis abdominalis pars subcutaneus abdominalis, Helm, no. 8, 1886: 558. Gadow and Selenka, 1891: 245. M. petoralis abdominalis pars posterior, Furbringer, 1888: 450. Beddard, 1898: 79. Hudson and Lanzillotti, 1964: 14. Id. dermo-pectoralis, no. 15, Shufeldt, 1890: 14. 13ermal component, M. pectoralis, no. 12 (5), George and Berger, 1966: 506. " 7 M79" 90 Description for Phasianus (Figures 10 and 12a).-- M. pectoralis thoracicus pars subcutaneus abdominalis is a dermal muscle covering the ventrolateral abdominal region. Pars subcutaneus abdominalis arises by a strong sheet of fascia which attaches to the dorsal border Of M. Obliquus abdominis externus, Os pubis, and the integument beneath and slightly lateral to the sternal and abdominal feather tracts. The belly (maximum width of about 40 millimeters at .its origin) narrows and courses anteriorly passing just Ilateral to the abdominal and sternal tracts. The muscle then czrosses the pectoral apterium to insert onto the skin beneath tine posterior and medialmost three to four follicles Of the puectoral tract. The belly, along its medial border, is firmly connected to the skin by fascia. £9nervation.--By a branch of N. pectoralis pars thoracica (== N. pectoralis abdominalis; Ffirbringer, 1888: 455). Comparison.--The facial origin, course, and insertion of pars subcutaneus abdominalis in ChI‘JSOlOJDhUS, Gallus, and Pavo is similar to that of Phasianus. The muscle apparently is equally deve10ped in most Galliformes, except for Coturnix Where it is extremely reduced (Hudson and Lanzillotti, 1964: :14) - 1" #. Fw_ :""‘""’" *‘flh ‘ _ .‘I 91 OTHER STRIATED MUSCLES ASSOCIATED WITH THE SKIN M, gastro—lumbalis (Mglm) This thin but wide (about 40 millimeters) dermal muscle is present in Gallus, absent in ChrysolOphus, Phasianus and £939, The muscle was apparently first described in Gallus by Helm (1884: 552; 1886: 541). M. gastro-lumbalis lies be- tween the anteroventral border of the femoral tract, where the muscle is firmly bound to it by dense fascia, and the posterolateral border of the sternal tract, where the muscle is bound to it by the fascial Sheet of M. Obliquus abdominis externus. The fibers course ventrally beneath the lateral body apterium and some may unite with fibers of M, pectoralis thoracica pars subcutaneus abdominalis. M. gastro-lumbalis appears to be a modification of the origin of M. pectoralis thoracica pars subcutaneus abdominalis (M. pectoralis pars abdominalis, George and Berger, 1966: 511). They stated that depending upon the degree of deve10p- ment pars abdominalis arises from the subcutaneus tissue of the pelvic region or from the thoracoabdominal region near the knee. The latter origin corresponds to M. gastro-lumbalis. I found both origins present in Gallus. George and Berger did not give any examples of representatives in which the muscle ‘was present nor did they give any reference which could be examined. This particular condition was not mentioned by Ffirbringer or by Gadow and Selenka. I have retained the terminology of Helm until further investigations can be made in more birds. 92 M, mylohyoideus posterior Probably M. platysma myoides, Owen, 1842: 24. NO. 5, Shufeldt, 1890: 6. Posterior portion of M. triangularis juguli, Helm, 1884: 556; 1886: 500. Posterior portion of M. mylohyoideus anterior, Mudge, 1905: 247. M. gularis, Edgeworth, 1955: 109. Description for Phasianus (Figure 11a).-—This is a trans- verse triangular sheet Of muscle covering the posterior ventral floor of the throat. The muscle is superficial to the deeper hyoid muscles. It arises fleshy from the post- articular process, at the posterior end of the lower jaw, ventral and posterior to the origin of Mm. stylohyoideus and serpihyoideus. M. mylohyoideus posterior, about 2 milli- meters wide at its origin, conceals the insertion of M. depressor mandibulae. It then fans out ventrally to join the same muscle from the opposite side at the mid-ventral line. Posteroventrally muscle fibers merge with the anterior part of M. constrictor colli. Mid-anteroventrally M. mylohyoideus posterior inserts on the interramal fascia in common with the posterior border of M. mylohyoideus anterior. M. mylo- hyoideus posterior is about 1.5 centimeters wide at its insertion. It is not attached to the hyoid bones nor to the deeper tongue muscles. 95 Innervation.--Branch of N. facialis (Gadow and Selenka, 1891: 507; Edgeworth, 1955: 109). Comparison.--The muscle is equally well developed in Chrysolophus and Gallus. It is least deve10ped in £939, where the origin, insertion and thickness of the muscle sheet are extremely small. I do not consider M. mylohyoideus posterior to be a dermal muscle. However, I found it necessary to describe it since it adhered to the overlying skin in some of my specimen preparations. For this reason the muscle could have been easily overlooked by previous investigators studying the tongue muscles or it may have been considered a dermal muscle by others (e.g., Helm, 1884: 1886). A muscle described as M. mylohoideus posterior is fig- ured for Rhea darwini (Gadow and Selenka, 1891: 506). It is confluent anteriorly with M. mylohyoideus anterior and posteriorly with M. constrictor colli. Gadow and Selenka divide M. mylohyoideus posterior into two parts: an anterior .M. stylo-hyoideus and a posterior M. serpi—hyoideus. This terminology has also been adOpted by Mudge (1905), Fisher and Goodman (1955), Goodman and Fisher (1962), and Weymouth ‘_£_9_, (1964). However, M. mylohyoideus posterior in the representatives I examined does not correspond to M. mylo- hyoideus posterior of Gadow and Selenka, nor does it corres- ;pond to Mm. stylohyoideus or serpihoideus of the investigators cited above. These muscles are also present in Phasianus, In. . \ .3 .F . étu 94 Gallus, Chrysolophus, and £9v_9 (Figure 11a). Mudge (1905: 248, 252) stated that the most primitive condition of M. mylohyoideus posterior (= his posterior gxxrtion of M. mylohyoideus anterior) is exhibited in Strigops habrgtilus where it takes the same origin as Mm. stylohyoideus and serpihyoideus. Mudge figured this muscle for StrigOpS (Plerte 26, Figure 2). Furthermore, he traced the step by step regression of M. mylohyoideus posterior to its complete disappearance in Nestor notabilis and Probosciger (Microglossus) (Mudge, 1905: 255) . Edgeworth (1955: 107) described and figured (Figure 619) M. gularis which corresponds to M. mylohyoideus posterior. He stated that the muscle is Simple in Gallus but that in some birds (e.g., Anas, Opisthocomus, 993:99 and Passer) the muscle is separated into 2 parts, Mm. gularis anterior and gularis Posterior. He apparently failed to recognize that Mm. serpi- hYOideus and stylohyoideus were also present in Gallus. I agree with George and Berger (1966: 252) who consider Mm. se{Pi-hyoideus and stylohyoideus homologous to the posterior and aJl‘tzerior parts, respectively, of M. gularis. An equally comprehensive study of the tongue musculature on the Galliformes, as done by Mudge for the parrots, would no dQubt reveal some interesting relationships among these musclfiis. At any rate this study has disclosed that the derivatives of the primitive constrictor sheet (Mm. constrictor C I 0111 . mylohyoideus anterior, mylohyoideus POSterior' 95 Figure 9.—-Internal view of the skin of male Phasianus colchicus showing the course, distribution and attachment of the striated dermal muscles associated with the dorsal pyerylae excluding the extreme anterior region of the dorsal capital tract. The solid lines within pterylae represent feather muscles which are superficial to the dermal muscula- ture. Drawn from a photograph of a whole mount. Bouin fixation, unstained and partially cleared. The dash line represents the boundary of the cut skin. Abbreviations of the Dermal Muscles: (see page 71 for other abbreviations) Constrictor colli con. colli Cucullaris pars cranialis (left side cut at cranial attachment and mid-cervical region; right side partially removed to Show superficial M. constrictor colli. CUC. cran . cer. 9, cuc. cer. = Cervical component of M. cucullaris pars cervicalis (cut). 9;, 9, cuc. cer. = Clavicular component of M. cucullaris pars cervalis (cut). lat. 9, 99, = M. latissimus dorsi pars dorsocutaneus (cut). ser. 9, mpt. = M. serratus superficialis pars meta- patagialis (cut). M. latissimis dorsi pars metaptatgialis (cut). I... r1. a B r,- ll ale Phasianus 1 and attachmen: with the dorsal egion of the data: :rylae represen: he dermal mesa:- mount. Bouifi The dash line page 71 for b- ; (left Side?" 1 mid‘cerv'lci‘ Llly removed If :rictor C011.“ of M. cucull- ut) - t of M. cucull‘i dorsocutzin?“s r5 met? is pa 5 metaptatgla/ 96 ————— Cuc. cran. :: ~.__. —V. Ce r. tr. l 0 ac. cr-n. ' Interscap, Ir. cer. c. Cue. con: l I cl. c. Cue. cor. Lat :1. dc. Interscap. apt. ‘ _ \‘v - “.vwgh V ‘9. 9 v‘ ('I ’ I 19 0 8.5 "’ 11“. 9.0 fl 0 ‘i « O Perlc tr. \‘ w "' “| . 0 4 \ ""!."’I ' p “i“ ‘ ‘9“ 2"" *1 Figure 9 97 Figure 10.--Internal view of the skin of male Phasianus colchicus showing the course, distribution and attachment of the striated dermal muscles associated with the ventral pterylae excluding the anterior region of the capital and ventral cervical tracts. The solid lines within pterylae represent feather muscles which are superficial to the dermal musculature. Drawn from a photograph of a whole mount. Bouin fixation, unstained and partially cleared. The dash line represents the boundary of the cut skin. Abbreviations of the Dermal Muscles (see page 71 for other abbreviations). cuc. cran. = M. cucullaris pars cranialis (cut in the mid-cervical region). .9. cuc. cran. = M. cucullaris pars cranialis (cut at the furcular attachment). pect. 99, sub. 99,)= M. pectoralis thoracica pars sub- cutaneus thOracicus (cut). pect. 99, sub. abd. = M. pectoralis thoracica pars subcutaneus abdominalis (cut). 1ale Phasianus 1 and attache: with the ventral the capital 3:: within pterylae icial to the ph of a whole ially cleared. he cut skin. age 71 £01013 alis (CUt ‘13.; anialis (Cut 5' nt) - oraCiCa Pars ;. ous (cut . noracica pat: minalis 98 Cuc. cran. reg. 01 mars. cov. Pen 1. u: . ‘-----‘ .~ Pool. ah. t: ' sub. 0h. A cky " '4 L Pact. m. sub. abd. Antorlor Figure 10 99 Figure 11.-—Left lateral view of the head and neck of make Phasianus colchicus showing the superficial musculature and the origin of the dermal muscles. A. Head M, cucullaris cranialis, 99, = the cranial attach- ment of M. cucullaris pars cranialis (cut). B. Neck Mm. cucullaris cervicalis, cer. = the cervical attachment of Mm. cucullaris pars cervicalis. M, cuc. cerv., 9;, = the Clavicular attachment of M. cucullaris pars cervicalis (retracted and cut). l and neckoinfi .al musculahre the cranialafli ialis (CUU- = the cervhfl :s cervicahs [lar attachment; -etracted'cmC M,mylohyoideus 100 cranualis. cr. M. cucullaris mandibulae mandibulae adductor M. depressor M. geniohyoideus M. mylohyoideus posterior M. serpi hyoideus anterior M.Stylohyoideus Mm. ascendentes cucullaris cervicls Mm. M.biventer cervica||5,cer. cervicis ‘i; V \ ." ‘\:§;3 I \ l——M. pectoralis thoracica Cerv.. cl. N. M.lo_ngus collnventralis Mm. intertransversarii M. cuc. dorsal spinal N. . ventral spinal Figure 11 l' ‘pr‘_ 101 Figure 12.--Dermal and superficial muscles of the trunk of male Phasianus colchicus. The skin is not removed from the distal portion of the right arm. (a) ventralxdew, (b) dorsal view. Abbreviations for the Dermal Muscles (see page 71 for other abbreviations). cuc. cer. = M. cucullaris pars cervicalis (Clavicular component). cuc. cran. = M. cucullaris pars cranialis (furcular attachment). pgct. thor. subcut. thor. = M. pectoralis thoracica pars subcutaneous thoracflnm. peCt- thor. subcut. abd. = M. pectoralis thoracica pars subcutaneus abdominalis. lat. dor. dorsoc. = M. latissimus dorsi pars dorso- cutaneus. lat. dor. met. = M. latissimus dorsi pars meta- patagialis. ser. sup, met. = M. serratus superficialis pars metapatagialis. ' 102 M' CI". cor. E the trail: :remOVed M. Cuc. tron. H37)“ /. . // l) ventral +22 M. '0‘.. 'hor. subcut.. chop, - ‘ w u_ Don. A‘- lot. dot. m... that. ;e 71 for at: M. POCO. Ohor.‘ "Nu-n. abd. ' n. on." IS (clamor: _ML .3... is (furcular is thoracra aneous thcfiv'» ; thoracica leUS abdc:;.::. _ Flgure 12 pars dare:- ; meta— ,s pars .anun- a»... 11H L11; 105 stylohyoideus, and serpihyoideus) are well deve10ped in flasianus, Chrysolophus and Gallus, and weak in E9. _MI_9. occipitalis, frontalis, demo-frontalis, circumconcha and dermo-spinalis Several investigators have found dermal muscles associ- ated with the forehead and crown in some birds. Helm (1884: 547, 557; 1886: .540) described M. occipitalis which he found only in the Crowned Pigeon Goiira cristata (Gofira coronata) and g. frontalis which he found in some gallinaceous birds and also in the Crowned Pigeon. Shufeldt (1890: 2, 4) described a muscle similar to the latter, M. dermo-frontalis, which he found only in the male Raven. These muscles were absent in the forms I examined. Also, I did not find any muscles which corresponded to Shufeldt's Mm_. circumconcha and dermo-spinalis. Llcroscopic Examination of Teased Dermal Muscle In most instances Sheets of dermal muscles could be easily Stripped from the undersurface of the skin. However. in certain regions portions of the dermal muscles firmly adhered to the skin beneath the feather follicles suggesting the Possibility that striated muscle might be attached to the follicle walls. In order to determine whether or not this were true, muscles attached to the follicles were teased free, removed, stained with hematoxylin and examined at 450x. '1“ . . lsSUe from the following areas was selected for examination: 104 (i) Mid-region of the dorsal cervical tract (hackle region of Gallus, Phasianus) where transverse fibers of M. constrictor colli are firmly attached. (ii) The insertion end of M. cucullaris pars cranialis at the point where a transverse line connecting the follicles of the marginal coverts intersects with a longitudinal line drawn through the mid-region of the ventral cervical tract (Phasianus, Gallus). (iii) M. cucullaris pars cranialis where it attaches to the skin beneath the follicles of the cape feathers in Chrysolophus pictus and g, amherstiae. (iv) The insertion ends of the cervical component of M. cucullaris pars cervicalis (Phasianus). (v) The insertion end of M. pectoralis thoracica pars subcutaneus thoracicus (Phasianus). In all instances the only type of muscle I found connected to the feather follicles was non-striated. Petry (1951) made a histological examination of the skin in the pigeon. He did not report finding striated muscle attached to feather follicles. He did find an interlacing of smooth muscle (musculoelastic tissue) and striated muscle present in the lateral cervical apterium. However, he did not state the source of the striated muscle fibers. I assume they were from the cucullaris complex. 105 Significant Morphological Findings M. mylohyoideus posterior, though found connected to the skin in some preparations, should not be regarded as a dermal muscle but probably rather as a "tongue" muscle. M. mylohyoideus posterior is described for Phasianus, Gallus, ChrySOIOphus, and Pavo. Tables 5 and 4 summarize the dermal muscles found in Phasianus, Gallus, Chrysolophus and Pavo. M. cucullaris pars dorsocutaneus is present in Chrysolophus and Pavo and absent in Phasianus and Gallus. M. gastro—lumbalis is present only in Gallus. Many dermal muscles described by previous investi- gators for other birds are not present in Phasianus, Gallus, ChrySOlOphUS and gayg. M. cucullaris is the most complex of the dermal muscles having attachments to the skin, skull, neck, appendicular muscles, and to the clavicle. It is not attached to the spinous processes of cervical vertebrae. The cranial component of M. cucullaris pars cranialis is relatively more deve10ped in male Gallus and Chrysolophus than in females of these genera. This may be related to the fact that display feathers overlie the muscle in males. M. constrictor colli is present beneath the hackle follicles of Gallus and absent beneath the follicles of the cape feathers in Chrysolophus. Except for the differences noted above, the course, origin and insertion of the dermal muscles do not differ 106 N .mMflumumnfim hm cam msuuwm magmmHOmNmzo .x. I I mauaooasoufio I mHHMHGOHMIOEHmQ “mflamucoum I I I I mflamuflmflooo I I I I mHHmGHQmIOEHmQ I I N I mflHMQEDHIouummw I I I I mflamflmmummmume mHHMCflEoon mflamuOuomm mflHMCHEOUQm msmcmusonsm whom mowomuonu mHHMHOqum >< N >< X >< N >4 X mDUflowuonu mswcmusoflom whom MUHUMHOSu mHHMHOuomm I I I I mzmcmuooomnoo mumm mHHMHUHmummsm msumuumm N X N X mHHMHmMummmqu mumm mHHMHonuwmsm msumnumm mamcmusooao mumm Hmuoo mDEHmmflumq N N N N mHHMHmmummmqu mumm Hmnoo msEflmmHumq N N N N msmcmuzoomuoo mumm Hmuov mSEHmmHumq N N N N Aucwcomfioo HmHDUfl>mHov mflamofl>umo mumm mflHmHHDUDU N N N N Aucmcomeoo HMUH>HmUV mfiam0H>umU mumm mHHMHHDUSU I I I I mflamwmmummmume mumm mflHmHHSUDU I I I I mdwcmHDUOEo mumm mHHmHHDUDU I I I I mHHMHmMummoum mnmm mHHmHHDUDo N N I I msmcmusuomuoo mumm mflHmHHSUSU N N N N . mHHMHcmuo mama mHHmHHsosu N N N N flHHoo HouUfiHumcou o>mm *mssmoHommuno msHHmw mscmwmmnm |II‘ 1" IN (I (I II .wucwmnm mmumoflGCH AIV .mmHmEmm 0cm mmHmE uHDUm CH wocwmmum mouMUHoCH N cfi .mucmmmmnm mo mumcmm w CH mmHUmDE Ameumv mo wonmunsouo m mqm¢B 107 .mHHmumU How mCOHumHHUmmU uNmu Op Hmmmm .Hmuucm> u .> “msoflomuonu u .Honu “Hmcuwum H .Hmum unwasmmum u .mmom “Hmuouomm u .uomm “mung u .m “HmumumH u .H “Hm0fl>umo u .umo “mHHmcHEOUQm u .onm upxmu mom Aev “mam: Hoaumumom Amy “mama Hoflnmucm ANV “mono nuon um aflxm on» on Umpomccoo Adv .Hmum .H N aN N mHHmQEsHIonummw Noon .H N N .uomm N N N .Unm wsmcmusunsm .m MUHUmHOSU mHHmuouumm .Honu msmcmusonsm .m N Noon .H N N N mHHMHmmquMumE .m mHHMHUHMHmmDm msumuumm .mmom N N N mfiHMHmumummumE .m mcoc N N N msmcmuooomuoo .m Hmuoo mafiamwflumq .umo .H N N N ucmcomeoo HMHDUH>MHU .Hmu .H N N ucmcomfioo HMUH>H00 mflamofl>umo .m moo: N N QN mDmGMUDUOmHoo .m .Hmo .> .m mHHmHHDUSU moo: N HN N flHHOU Houofluumcoo commouo moamumum mmamumum cam numcma maomze coum aflxm Esflumum< mo Hmouon gummamm moo wuflucm hoom Iamxm ms» um um macaa mmusoo :me mnu ouco cofluummcH camfiuo .mmaomDE Hmfiumo mnu mo mmHDOU cam coauummcfl .cflmfluo d Wflmfifi 108 significantly between Phasianus, Gallus, ChrysolOphus, and ‘ggyg, nor between males and females of these genera. Although differences exist in the course, origin, dis- tribution and site of attachment to the skin between indi- vidual muscles, common characteristic features of the dermal muscles as a group are: (1) They are striated muscles. (ii) They are in the form of thin sheets or bands. (iii) They do not attach to individual feather follicles. (iv) Some portion of the muscle attaches to the under- surface of the skin by connective tissue or fascia. Some dermal muscles are confined solely to the skin; that is, they have both their origin and insertion restricted to the skin (e.g., Mm. constrictor colli, cucullaris pars dorsocutaneus, gastro-lumbalis). Of these only M. con- strictor colli is bound to the skin along its entire length. With respect to origin some dermal muscles arise from the skeleton (e.g., M. cucullaris pars cranialis, the clavi- cular component of cucullaris pars cervicalis). Other dermal muscles arise from a body muscle (e.g., the cervical com- ponent of M. cucullaris pars cervicalis, Mm. latissimus dorsi pars dorsocutaneus and pars metapatagialis, Mm. serratus superficialis pars metapatagialis, pectoralis thoracica pars subcutaneus thoracicus and pars subcutaneus abdominalis). At their insertions, some dermal muscles are firmly bound to the skin along most of their length (e.g., 109 M. constrictor colli, the anterior portion of M. cucullaris pars cranialis, Mm. pectoralis thoracica pars subcutaneus thoracicus and pars subcutaneus abdominalis). M. pectoralis thoracicus pars subcutaneus abdominalis is firmly attached along its medial border. Most dermal muscles are firmly bound to the skin at the insertion end only (e.g., M. cucullaris pars dorsocutan- eus, the posterior half of M. cucullaris pars cranialis, the Clavicular component of M. cucullaris pars cervicalis, Mm. latissimus dorsi pars dorsocutaneus and pars metapatagialis, M. serratus SUperficialis pars metapatagialis). Attachments to the skin are beneath the follicles of feather tracts (e.g., M. constrictor colli, the anterior half of M. cucullaris pars cranialis), or at the edge of feather tracts, generally beneath groups of feathers border- ing feather tracts (the posterior half of M. cucullaris pars cranialis, Mm. cucullaris pars dorsocutaneus and pars cervicalis, latissimus dorsi pars dorsocutaneus and pars metapatagialis, pectoralis thoracica pars subcutaneus abdominalis and pars subcutaneus thoracicus, serratus super- ficialis pars metapatagialis). All dermal muscles except Mm. constrictor colli and cucullaris pars dorsocutaneus course beneath apteria. This may be significant in aerodynamics. The action of such a muscle may draw the borders of two feather tracts closer together thus making the feathers of one tract overlap more 110 'with those of an adjacent tract. This would probably result in a more uniform contour of the plumage which allows for a smoother passage of air over the surface of the body dur- ing flight. In the birds I studied dermal muscles are not associ- ated with all feather tracts. They are not attached to the skin beneath follicles of the dorsal, capital, crural and ;pelvic tracts, nor are they attached to the skin bordering these tracts. The common feature is that in these regions the skin is tightly bound to the body. In contrast to this situation 6 dermal muscles are associated with the loose skin of the neck. Action of the Dermal Muscles Morphological evidence.--The action of the dermal Inuscles must first be determined before their relationships 'to feather display can be ascertained. My deductions of Inuscle action are based primarily upon morphological evidence rsal cervical spinal roots produced twitching and folding (hf the skin which caused groups of feathers in the inter— EBCapular region to draw closer together. ~Again the feathers Ileither elevated nor depressed. Folding and twitching of 118 1:he skin were most noticeable in the region of the lateral <:ervical apterium when ventral cervical roots were stimu-‘ lated. This is because ventral roots innervate the cervical <:omponent of M. cucullaris pars cervicalis. When the muscle contracts, a region of the skin corresponding to the in- sertion is tightened and pulled inward toward the origin at the neck. These findings SUpport my deductions of muscle action 'based upon morphological data, suggesting again that the action of the dermal muscles is to move the skin rather than to control elevation of the feathers. In general, my pre- liminary physiological experiments verify some of the find- ings of Langley (1904). He found that stimulating ventral cervical roots produced a sharp twitch of the striated Inuscles associated with the neck. Langley found that stimu- lating peripheral nerves produced depression of the feathers. TPhis response is similar to that produced when the sympathe- 1:ic system is stimulated. I could not produce feather Ver. All birds apparently recovered completely. In general, they exhibited normal behavior patterns associated With feeding, crowing and body maintenance, 24 hours after the oL'Jeration. One noticeable difference in postoperative birds appeared to be a slight drOOping of the head. This In . . . ay have been due to the destruction of pars cranialis, 122 which in its intact form may help to keep the head in an upright position, or it could be attributed to the lingering effects of anesthesia. Drooping of the head diminished 24 hours after the Operation. Muscle extirpations were not made in all cocks on the same date (Table 5). Some birds. served as controls early in the experiment but after 21 days all cocks had had the Operation, at which time the experiment was terminated. After a period of isolation (1 to 5 days) eXperimental birds were reintroduced into the flock and observed for 10 minutes. If the experimental cock was submissive it was isolated again and reintroduced at another time, sometimes into the pairing territory Of another breed (Araucana) . The Araucana was selected because it always provoked agonis- tic displays when it was introduced into the territory of eXperimentals . Table 5 shows that shaking of the body, frontal display or submissive behavior was performed by introduced cocks; the response apparently depended upon the social structure 0f the flock. Frontal displays were frequent between bird 2 and bird 5. These birds ranked 1 and 2 respectively in the l”13'.erarchy before and after muscle extirpation. All birds were submissive when introduced into the breeding territory Of a foreign bird (Araucana) . When the Araucana was intro— duced into the flock, all 6 birds challenged him with frontal disp lays . s . 4 t q .3. . .. . . i I: . -.._ '1. I mumiflF—w—d— 125 FOOTNOTES TO TABLE 5 (1) The first column is the date birds were resub- mitted to rivals. In the second column the number on the left refers to the number of days subsequent to muscle extirpation; the number in parentheses is the number of days the birds were isolated prior to resubmitting to rivals. (2) + indicates the hackles elevated; 0 indicates hackles not elevated. (5) Birds were considered submissive when they did not challenge rivals with a frontal display. Shaking of the body was recorded since it involves the movement of feathers. (4) A cock Araucana introduced into the territory of Rhode Island Reds. (5) Bird introduced into the territory of paired Araucanas. TABLE 5 124 Fmsponses of cock Rhode Island Red chickens to rivals after partial removal (1g5 cm) of M. cucullaris pars cranialis from its cranial attachment . Operation Exposed Behavior to Ifird Type Date rivalsl Hackles2 Display3 Directed toward 1 Sham 5/7 5/11 4(4) + Body shake Flock Bilateral 5/25 5/28 5(5) 0 Submissive Flock 5/28 5(5) + Frontal Araucana4 2 Bilateral 5/7 5/11 4(4) + Body shake Flock 5/14 7(1) 0 Submissive Araucana5 5/15 8(2) + Frontal Bird three 5/22 15(0) + Frontal Bird three 5/26 19(1) + Body shake Flock 5/28 21(0) + Frontal Araucana 5 Control 5/7 5/11 (4) + Body shake Flock 5/15 (0) + Frontal Bird two Bilateral 5/17 5/18 1(1) 0 Submissive Flock 5/22 5(4) 0 Submissive AraucanaS 5/22 5(4) + Frontal Bird two 5/25 6(1) 0 Submissive Flock 5/28 11(1) 0 Submissive Flock 5/28 11(1) + Frontal Araucana4 4 Control 5/17 5/18 (1) 0 Submissive Flock Bilateral 5/21 5/22 1(5) 0 Submissive Araucana5 5/22 1(5) + Frontal Hen 5/25 2(1) 0 Submissive Flock 5/27 6(1) 0 Submissive Flock 5/28 7(0) + Frontal Araucana4 5 Control 5/17 5/18 (1) 0 Submissive Flock Control 5/17 5/22 (4) 0 Submissive AraucanaS Bilateral 5/25 5/26 5(5) + Body shake Flock 5/27 4(1) 0 Submissive Flock. 5/28 5(1) + Frontal Araucana4 6 Bilateral 5/25 5/25 2(2) + Frontal Hen 5/27 4(1) 0 Submissive Flock 5/28 5(1) 0 Submissive Flock 5/28 5(1) + Frontal Araucana4 \ * RGfer to the key to Table 5, page 125 for details. 125 During frontal display both the experimental and the control birds elevated their hackles (Figure 4; the banded bird is bird 2, eight days after the Operation). Hackles appeared to raise as quickly and as high in experimentals as in controls. The remaining body feathers were strongly *2? depressed in both birds. Movements of the body and feathers 1. I did not appear to differ among experimentals and controls. a} 0. II Experiments were terminated on 28 March, 1967 and each bird was anesthetized and reexamined for the degree of re- generation Of M. cucullaris pars cranialis. I found no apparent adhesion of the muscle to the skull 5, 7, 11 and 21 days after the cranial portion had been extirpated. Results from these experiments demonstrate that partial destruction of M. cucullaris pars cranialis does not affect the degree of elevation of the hackles in Rhode Island Red chickens. Thus, morphological and physiological evidence, and evidence from muscle extirpations in live birds, support the hypothesis that the action of the striated dermal muscle is to position the skin rather than to regulate the degree Of elevation of individual feathers. §ummary and Discussion Generalizations about the morphology and action of the dermal muscles apply only to the birds I examined. The gross morphology of 10 striated dermal muscles is described for Phasianus, Gallus, ChrysolOphus and Pavo. 126 Mm. constrictor colli, cucullaris pars cranialis, cucullaris pars cervicalis, latissimus dorsi pars dorsocu- taneus and pars metapatagialis, pectoralis thoracica pars subcutaneus thoracicus and pars abdominalis are present in both sexes of all representatives. The course, origin and attachments of these musclescknnot differ significantly between sexes or among representatives. Mm. cucullaris pars dorsocutaneus is present only in Chrysolophus and gayg. M. gastro—lumbalis, present only in Gallus, may be a dermal component of M. pectoralis thoracica pars abdominalis. M. mylohyoideus posterior is not considered a dermal muscle but rather a I'tongue" muscle. It is present in Phasianus, Gallus, Chrysolophus and 2339, As a group, dermal muscles may be attached to the skele- ton Or to appendicular muscles and are always attached to the skin at one end. Mm. constrictor colli, cucullaris pars dorsocutaneus and gastro-lumbalis have both their origin and insertion restricted to the skin. M. cucullaris pars cervicalis and the Clavicular com- ponent of M. cucullaris pars cranialis arise from the skeleton. The cervical component of M. cucullaris pars cervicalis, Mm. latissimus dorsi pars dorsocutaneus and pars metapata- gialis, Mm. serratus superficialis pars metapatagialis, pectoralis thoracica pars subcutaneus abdominalis and pars 127 subcutaneus thoracicus appear to be dermal components of body muscles. Dermal muscles do not attach to individual feather follicles. Rather, they attach by fascia to the undersurface of the skin, generally beneath groups of feathers at the borders of feather tracts. They usually cross apteria. ; No dermal muscles are found associated with the dorsal ) capital, crural or pelvic tracts. Six dermal muscles are associated with the loose skin of the neck. Deductions of muscle action were made, based upon morphological evidence and evidence obtained from eXperi- ments in muscle and nerve stimulation and muscle extirpa- tions in live birds. Actions of individual muscles are assumed to depend upon the origin, course, and insertion of the muscle(s) contracting and Upon the elastic nature of the skin within pterylae and apteria. The evidence strongly suggests that the action of the dermal muscles is to tense and tighten the skin, not to regulate the degree of elevation of the feathers. Tensing and tightening of the skin probably serve many functions. Some factors which might play a role in the development and function of M. cucullaris, the most complex of the dermal muscles, were considered and discussed pre- viously. These included multiple innervation, the mobility of the head and neck, the functioning of the esophagus, 128 trachea, crop and cervical air sacs, and the contour of the body as related to flight. The phylogeny of M. cucullaris may also provide some insight as to its function in birds. Although he does not discuss the functional relationships of M. cucullaris, Edgeworth (1955: 141-155) presents a detailed account of its deve10pment among vertebrates. He stated that it deve10ps as a backward extension of the caudal-most branchial muscle plates in Dipnoi, Elasmo— branchii, Teleostomi, Amphibia, Reptilia and Mammalia. In general, the muscle arises from the skull and passes to the scapula, clavicle or to the sternum. Apparently it is absent in limbless forms (e.g., Urodela, Ophidia) and in some teleosts which have a fixed pectoral girdle (e.g., Acipenser sturio). It does not develOp in Anura until metamorphosis. This suggests that M. cucullaris may be related to coordinated movements between the skull and the skeletal components of the pectoral girdle which in turn may be associated with locomotion. Edgeworth stated that in some forms in which the shoulder girdle is rudimentary most of the fibers of M. cucullaris pass from the skull to the skin (e.g.,Amphiébaenndreptiles). This modification in attachment of M. cucullaris may be an adaptation for the fossorial habits of these forms. In reptiles M. cucullaris develops from the 2nd branchial muscle plate. In birds the 2nd branchial muscle plate is not 129 formed. Edgeworth (pp. 146, 155) does not accept the ist branchial muscle plate as the source of the cucullaris. He describes M. cranio-cervicalis which deve10ps from occipital myotomes and has the same function as M. cucullaris but is of different development than in reptiles. He does not consider M. cranio-cervicalis homologous to M. cucul— laris. I have retained the terminology of M. cucullaris because of its widespread acceptance in the avian literature, and until more evidence is available on the homologies of flit-"rt. ‘r—r‘m‘fiq this complex muscle. The prOposed actions and functions of the dermal muscles found in Phasianus, Gallus, Chrysolophus and gayg are sum- summarized below. The first 6 muscles are assumed to inter- act with one another to control the loose skin of the neck. M, constrictor colli probably tightens the skin around the anterior neck. The action may aid in passing food down the esophagus. The cranial component f M, cucullaris pars cervicalis presumably tightens the skin of the anterodorsal and lateral neck. Since it is relatively more deve10ped in male of Gallus and Chrysglgphug than in females of these forms, its development appeared to be related to the displays of these birds. However, experiments in muscle stimulation and extirpation of the cranial attachment in live birds demon- strated that the muscle is not responsible for elevating the hackles in Gallus. It may play a more important role in 150 supporting the skin against shearing stresses, aiding in regulating the mobility of the head and neck, and aiding in passing of food down the eSOphagus or passing of air through the trachea and cervical air sacs. The furcular component 9j_M, cucullaris pars cranialis is intimately associated with the crop. Contraction of the muscle probably tightens the skin over the crOp, thus per- ,i---r.. _ “slur—n .. . . .9 .. haps supporting this organ and possibly aiding the passage of food through it. M, cucullaris pars dorsocutaneus, a dorsomedial posteri- or continuation of the cranial component of M. cucullaris pars cranialis, appears to supplement the action of the latter in tightening the skin between the skull and the interscapular tract. It is present only in Chrysolgphus and 2m. Slips of the cervigal component g£_M, cucullaris pars cervicalis arise from the lateral surface of the neck and pass posterodorsally to insert onto the skin beneath the lateralmost follicles of the interscapular tract. Electri- cal stimulation of the muscle results in the folding of the skin in the lateral cervical apterium and drawing of the skin inward to the lateral surface Of the neck. The action may aid in the expulsion of air from the cervical air sacs or in the control of the flow of air over the thoracic region Of the neck. The Clavicular component of M, cucullaris pars cervi- calis arises from the dorsal medial border of the clavicle 151 and inserts onto the skin beneath the lateralmost follicles of the interscapular tract just posterior to the insertion of the cervical component. The muscle presumably tightens the skin which may aid in controlling the flow of air over the shoulder during flight. M, latissimus dorsi pars dorsocutaneus acts upon the skin of the interscapular tract and appears to be antagonistic to the action of the cranial component of M. cucullaris pars cranialis and also M. cucullaris pars dorsocutaneus when the latter is present. M. latissimus dorsi pars dorsocutaneus presumably draws the skin beneath the interscapular tract posteriorly. M, latissimus dorsi pars metapatagialis presumably tenses the skin between the dorsal thoracic region and the meta- patagium and M, serratus superficialis pars metapatagialis tenses the skin between the lateral thoracic region and the metapatagium. These two muscles may interact to control the flow of air beneath the shoulder. M, pectoralis thoracica pars subcutaneus thoracicus probably tenses the skin over the anterior thoracic region. The action presumably is to draw the skin of this region dorsally and anteriorly toward the axillary region. The action may be important in controlling the flow of air over the lateral surface of the body. M, pectoralis thoracica pars subcutaneus abdominalis acts upon the skin of the ventrolateral thoracic and .m: 152 abdominal regions. Its action appears to be antagonistic to M. pectoralis thoracica pars subcutaneus thoracicus (i.e., to draw the skin caudally and ventrally and to tighten it against the ventrolateral thoracic and abdominal wall of the body). The action may play a role in controlling the flow of air over the ventrolateral surface of the body or in the h expulsion of air from the abdominal air sacs. ‘ M, gastro-lumbalis is present only in Gallus. Its action apparently is to tense the skin between the antero- } ventral border of the femoral tract and the posterolateral border of the sternal tract. Relationship Of the Dermal Muscles to Feather Display I have previously described the movements of body feathers during display and during preening. In general, two different types of feather movements were assumed to occur. In the first type, feather shafts appeared to move independ- ently of the movement of the skin. In other words the feathers may move in one direction and the skin may move in another direction or remain stationary. rObservations of movements of the skin and of clipped feathers during preening of the pelvic tract in Gallus re- vealed that the skin of this area did not move as the feathers erected or depressed. Since striated muscles are absent from the pelvic tract in all representatives, some other mechanism must be responsible for raising and lowering the feathers of this area. 155 I have assumed that some movement of the feathers is dependent upon the movement of the skin. Observations of the skin and of clipped feathers of the dorsal neck of Gallus during preening revealed that the skin and feathers of the dorsal cervical tract may move anteriorly or posteriorly. Integrated movements of the skin and feathers appeared to be coordinated with the extension and retraction of the head ( and neck. The presence, location, attachments, contraction and T action of the cranial component of M. cucullaris beneath the dorsal cervical tract, and of M. latissimus dorsi pars dorso- cutaneus beneath the interscapular tract do exPlain this type of feather movement, but fail to explain elevation of the hackles during display. The contraction of the cervical component of M. cucul- laris pars cervicalis apparently eXplains the observed inward folding of the skin of the neck when clipped birds were handled. Hackle feathers are elevated and remain elevated during the frontal diSplay of Gallus even though the head may take many different positions. Elevated hackles may move closer together or further apart (anteroposteriorly) depending upon the position of the head. This form of feather movement is assumed to be under control of the skin which appears to be activated by M. cucullaris. I previously mentioned that swelling and shrinking of the body was most conspicuous and was unilateral during the 154 lateral diSplay of ChrysglOphus. It may be that control of inflation and deflation of the air sacs, and the size of the thoracic cavity is dependent upon the tension of the skin on the thoracic and abdominal wall of the body. Mm. pectoralis thoracica pars subcutaneus thoracicus and pars 37 subcutaneus abdominalis are positioned over the ventro- thoracic and abdominal region of the body. Activating the skin of the region by these muscles may explain the compressed shape of the body occurring during the courtship display of ‘r—nr - Chrysolophus. In the lateral display of Chrysolophus the yellow feathers of the rump appeared to shift toward one side of the body for which I proposed the movement of the skin as an explanation. However, since dermal muscles are not associ- ated with the skin of the pelvic tract, another mechanism must be present to explain the shifting of the plumage of the rump in Chrysolophus. The gross morphology and action of the dermal muscles, one component of the skin muscles, fail to explain: 1. The movement of feathers independent of the movement of the skin. 2. The elevation and depression of feathers during preening of particular feather tracts. 5. The general fluffing of all body feathers in the courtship display of Phasianus. 4. The inclination and elevation of the "ear" tufts in Phasianus. 155 5. The ruffling of the hackles and depression of the remaining body feathers in the frontal display of Gallus. 6. The extension and elevation of the cape in the lateral display of Chrysolophus. 7. The shifting of the plumage of the rump to one side of the body in the lateral display of ChrysolOphus. 8. The raising and spreading of the train in 2319. 9. The apparent permanence of the erected crest of .gayg and the depressed crest of ChrysolOphus. Though the dermal muscles appear to be the mechanism which activates the skin, they fail to explain the mechanism which activates the feathers. The second component of the skin muscles is the smooth muscles. This system will be examined next in an attempt to determine their role in feather display. v‘.‘-e.d .np #35,) ' | SMOOTH MUSCLES OF THE SKIN Introduction While the striated dermal muscles attach to the under- ?’ surface of the skin, the non-striated muscles Of the skin are confined within the dermis. Within pterylae, bundles Of smooth muscle (feather muscles) link adjacent feather fol- licles. A delicate layer of musculoelastic tissue, character- ized by an alternating series of smooth muscle fibers and elastic tendons, spans some apteria. Feather muscles of follicles at the borders of feather tracts and of isolated follicles in apteria unite with the musculoelastic tissue. Concurrently, but independent of this study, Dr. A. M. Lucas and his associates of the U. S. Department of Agri- culture Avian Anatomy Investigations at Michigan State University undertook an extensive investigation of the feather muscles (= their musculi pennati) and the musculo- elastic tissue (= their musculi apterii) in the chicken, turkey, coturnix, white Pekin duck and the common pigeon. They investigated the relationship of the smooth muscles to feather type and to patterns of pterylosis. Their studies were made at the gross, subgross and microsc0pic levels. They also investigated the micro-morphology of the innerva- tion and vascularization of the skin. 156 157 Although specific goals differed between their studies and mine, the approaches at the gross and subgross levels were similar. Also since my study concerns the relationship of the feather muscles to contour feathers which are posi- tioned conspicuously during display, feather type and feather pattern could not be ignored. For this reason my findings of noteworthy similarities or differences in the relationship of the smooth muscles to feather type or pterylosis are com— pared with those Of Lucas and Stettenheim (unpublished).1 The plan in this investigation of the smooth muscles is similar to that used in the examination of the dermal muscles. The basic pattern, distribution, arrangement, attachment, and extent of deve10pment are first presented for Phasianus _gglchicus. Similarities and differences in the gross mor- ;phology of the feather muscles as found in Gallus, £333, aund Chrysolophus when compared with Phasianus are noted and then related to feather display. Patterns of the muscoloelastic tissue are described tuit not figured. The arrangement Of the feather muscles of thus wing and tail was not investigated. For these details thug reader is again referred to the descriptions and excel- lerrt figures of Lucas and Stettenheim (unpublished). 1The reader is reminded that this citation refers to the Inanuscript Of "Avian Anatomy. Integument," currently in the Process of final editing; the manuscript will be pub- élsrhed for the U. S. Department of Agriculture by the Overnment Printing Office. .| 513K." .7. w-n 1' .‘ .21. 158 The basic arrangement, attachment and distribution Of the feather muscles are most easily demonstrated in regions of the body where the skin is thin and dermal muscles are absent. The femoral and crural tracts are two such regions, and skin from these areas are examined first. Femoral Tract Description for Phasianus (Figures 15, 14, and 15).-— The pattern of pterylosis as viewed from the external sur— face shows the feather follicles arranged in indistinct chevron-shaped rows with the apex Of the chevron pointing anteriorly (Figure 6). This pattern is most evident in the middle of the tract and becomes more Obscure at the dorsal and posterior boundaries. When a whole mount of the tract .is made and the gross pattern of feather muscles and follicle Itnvs is considered, a completely different picture is ob- tained (Figure 15) . The pattern of chevron-shaped follicle rows is not evi- dent. Using a mid-dorsal longitudinal line as a reference, nqucle and follicle rows course anterodorsally and postero- dcxrsally. Anterodorsal and posterodorsal follicle rows are non: always in a continuous line across the entire tract. Intercalary rows of follicles frequently interrupt the con- tinuous pattern. An intercalary row is identified by 2 or more follicles aligned in a row which is between, and ShCfl?ter than, two longer continuous rows of the tract. ‘3- l’ 159 Intercalated rows may be irregular (Figure 15A) or uniform (Figure 15B). Although intercalary follicles are a part of the total picture of pterylosis, they do not conform to the unusually clear pattern of follicle row arrangement found in the middle of the tract. Since they are ruptive to the pattern, I consider them different from the rest of the tract follicles. Anterodorsal and posterodorsal muscle rows are about equally developed except at the posterior part of the tract where posterodorsal rows are dominant. Muscle rows are sub— sequently considered dominant over other muscle rows when the muscles of one row stain darker than another row. Larger muscles stain darker than smaller muscles. Intersections of posterodorsal and anterodorsal muscle Itnvs connecting four contiguous follicles form subpatterns (nonsisting of diamonds, squares, or parallelograms. A feather iiallicle is present at each intersection. Orientation of fEnather follicles indicates that feathers might overlap the knase of a feather diagonally across from it if feathers were pxnssent. Longitudinal diagonal muscle rows are infrequently PINasent and if equally developed with respect to the antero- d£rrsal.and posterodorsal muscle rows they divide the quadri- lainaral into two prominent triangles. Closed quadrilaterals anti triangles are not present along the outer border except at 1ihe caudal region of the tract. Rather, feather muscles radiate and unite with the musculoelastic tissue characteristic 140 Figure 15.--External view of the skin covering the left thigh of a male Phasianus colchicus showing feather muschm of the femoral tract. A--The locatiOn from which Figure 14 was”made. B—-Intercalary follicle rows. C-—A point where diagonal muscles become dominant anteriorly. This causes a more acute curve in the posterodorsal direcum muscle rows. Change in direction of muscle rows resultsin a slight reorientation of quadrilaterals. The solid lines within the tract represent featherxmm- cles. Fine lines radiating out from isolated follicles represent feather muscles which connect to the musculo- elastic tissue (= apterial muscles) characteristic of most featherless spaces. The pattern of the musculoelastic tissue is not shown. Feather follicles are shown to demon- strate their variation in size, their orientation, and then: position relative to the epidermal surface. The drawing was made from a Kodachrome slide taken of a whole mount. Bouin fixation, unstained and partially cleared. 141 M. tanner pioryluo femoral-II n:| Hip region B _ 3R 1 . II I I a I I .0. ' ‘ O o I I \ 0" ’ .o - C I . -- -- I . . .\ O ' ’ .' p /, I - fin... .- . . I o - -., .I#2-‘ I " -.. 4% -s . l .‘r dot l ' I‘ so 3’ \ . .'_ ;‘, \ l. . | , . postorlor .. \ , .- a ’ I “"0. f."0n——>x ._ Figure 15 F" a V s _- ‘wEL-ur .9111 ~ in I 140 Figure 15.--External view of the skin covering the left thigh of a male Phasianus colchicus showing feather muscles of the femoral tract. A——The location from which Figure 14 was made. B——Intercalary follicle rows. C--A point where diagonal muscles become dominant anteriorly. This causes a more acute curve in the posterodorsal direcufl muscle rows. Change in direction of muscle rows resultsih a slight reorientation of quadrilaterals. The solid lines within the tract represent featherxmm- cles. Fine lines radiating out from isolated follicles represent feather muscles which connect to the musculo- elastic tissue (= apterial muscles) characteristic of most featherless spaces. The pattern of the musculoelastic tissueis not shown. Feather follicles are shown to demon- strate their variation in size, their orientation, and then: position relative to the epidermal surface. The drawing was made from a KodachrOme slide taken of a whole mount. Bouin fixation, unstained and partially cleared. 141 M. tensor pterylae femorolnle Hlp‘ region—1‘8 -$§ ‘53- My I -e. 0.. k I I; o . . - . ‘ . ‘ ~ .. e i ‘8 dorsal / . \ .’ o ‘ '. ' " a I ‘O I posterior Figure 15 f. {I V \ e :0 . \ Q 0 e ‘.. 0 -fl \ h. ' / {/2 l 'r ' ‘3. I .. o v . \ r.- /. . . '3‘ I ‘L- I I. r- I_ .°.' ': \ I‘ in. i ' ' ‘ } I ’ I ‘l 1 . 3 “s ‘e ‘ 4),. a . ‘ . '.-..a in- ‘\ \\ ~\\ .‘. \ i 142 of apteria. Musculoelastic tissue is least deve10ped at the caudal border of the tract. Triangles are most noticeable in the anterodorsal region of the tract where intercalary follicle rows are found (Figure 15B). Analysis of the feather muscles at the gross level indi— cates that where rows of intercalary follicles occur, a change in the direction of dominant muscle rows also occurs. It appears that the diagonals become progressively stronger anteriorly in such a way that the posterodorsal muscle rows Will-H ~'i.‘"“‘- ‘A—fi'T—IEY are shifted one-half of a row anteriorly. The diagonal muscle rows then predominate and account for the strongly curved feature of the posterodorsal muscle rows in this region. The former posterodorsal muscle rows become faint diagonals and the former diagonals reform a dominant pattern of new quadrilaterals. Thus, the pronounced presence of triangular subpatterns within a tract may indicate that the direction of muscle rows has changed. The basic arrangement and attachment of feather muscles connecting four contiguous follicles in the middle of the femoral tract are illustrated in Figure 14. Feather muscles course from the outer end (neck) of one follicle to the inner and (bulb) of adjacent follicles. A smaller band-like elevator muscle passes on each side of the single larger band-like depressor. Depressors are cord-like in the pos— terior region. Interdigitation of elevator and depressor muscle fibers is infrequent. In the middle of the tract the a (”imam 'l..__.t_!_l._‘ N ' ' u 145 Figure 14.--Internal view of a quadrilateral showing Una basic arrangement and attachment Of the feather muscles to four follicles in the mid-region of the left femoral tract Of Phasianus colchicus. The drawing was made frmn a Kodachrome slide taken at 20X under a dissecting micny- scope. Bouin fixation, unstained and partially cleared. Tendon \Noll dorsol anterior 144 Figure 14 145 non-striated muscles attach perpendicularly to the follicle wall. Attachment is by elastic tendons. Combined contrac- tion of the depressor muscles would probably pull the outer end of the follicle, and the feather shaft extending from it, closer to the epidermal surface. The elevators, would probably move the feather shaft away from the epidermal surface. These actions have been prOposed by Langley (1904). Feather musculature is most dense and complex in the posterior portion of the tract where feather follicles are long and close together in the anterodorsally directed rows. The muscle pattern in this area is further complicated by the presence of several rows of intercalary follicles with 2 to 5 follicles in each row (Figure 15A). A change in the direction Of muscle rows of the principal follicles is not evident at the gross level. At the subgross level a basic pattern Of quadrilaterals is still evident (Figure 15). Muscle rows course anterodorsally and posterodorsally between four contiguous intercalary follicles and between four con- tiguous follicles characteristic of the tract. In the latter, elevators and depressors are well deve10ped in both the anterodorsal and posterodorsal rows. In the quadrilateral connecting intercalary follicles both elevators and depressors are found only in the posterodorsal rows. Anterodorsal muscle rows have either depressors only or well developed muscles (retractors) which attach to the neck end of the follicles. Contraction of retractors apparently causes the follicles ' . .2’ WA] 1 *‘u; . - ‘ Lin-- 146 Figure 15.--Internal view showing the arrangement and attachment of feather muscles to follicles at the caudal border of the left femoral tract of a male Phasianus colchicus. Refer to Figure 15A for the location from which the drawing was made. Intercalary follicles are shaded. The drawing was made from a Kodachrome slide takenan 15X under a dissecting microsc0pe. Bouin fixation, unstained and partially cleared. 147 0.5 CM Depressor Muscles llevotor ‘ , ‘ \; Muscles Ietrostor Mossl es oMerlor Onrerodersol / ’0'. p°"Ol'o(loI-sol rows Figure 15 -- - ~. WW 148 to move closer together without elevating or depressing the feathers. Since these retractors are attached tangentially to the feather follicle, rotation of the feather probably also occurs. Muscles connecting one intercalary follicle with two follicles typical of the tract form a triangular subpattern. Examination of one triangle at the subgross level reveals that an intercalary follicle is connected to a regular tract follicle which is anterior and dorsal to it by a retractor muscle only, and connected to a follicle which is anterior and ventral to it by both depressors and elevators. Con- sidering that the presence of both elevators and depressors is characteristic of the tract, it appears that in the caudal region anterodorsal intercalary follicle rows are shifted one-half of a row dorsally. Retractor muscles are well deve10ped along most of the caudal border of the tract. They cover the outer one-third of each follicle and extend posterodorsally for 5 to 7 follicle rows. Fibers of the retractor muscles widen and then depart from the tract as a thin sheet and cross the pelvic apterium. Lucas and Stettenheim (unpublished), first described the muscle sheet (which they found moderately deve10ped in the chicken and strongly deve10ped in the turkey) as a tensor of the femoral tract (M, tensor pterylae femoralis). From its attachment to the follicles it appears that Contraction of this muscle moves the feathers dorsally ‘11-'57“ 7"." '. ‘ _ ~_.’., .€_ .‘.1.' .. ‘ 4 ".1 149 along the lateral surface of the thigh but without elevat- ing or depressing them. Lucas first postulated that this muscle might act to reduce the drOOp of the feathers of the femoral tract. However, after he transected the muscle no drooping of the feathers was observed. He suggested that further experiments were needed. Comparison.-—The general shape of the femoral tract and orientation of muscle rows are similar in Phasianus, Gallus, ChrysolOphus and £219. Equally dominant muscle rows consisting of flat double elevators and band-like single depressors course antero- and posterodorsally in Phasianus, Gallus and ChrysolOphus. Some diagonal muscles are present. In 23E posterodorsal muscle rows consisting of thin flat elevators and thin flat depressors are dominant. Generally, depressor and elevator muscle fibers interdigi- tate with each other. Anterodorsal muscle rows have tendons located mid—way between adjacent follicles. Tendons occupy one-fifth to one—third of the total distance between the r'ollicles and generally are restricted to the depressor uscles . Interdigitation of depressors and elevators, and re presence of tendons mid-way between the follicles, are oical throughout the femoral tract of PM except for :o 6 follicles of each row at the caudal region. Here i-tendons are absent and muscle arrangement is similar that in Phasianus, Gallus and ChrysolOphus. 150 M, tensor pterylae femoralis is least develOped in Pavo, moderately deve10ped in Phasianus and Gallus, and strongly developed in ChrysolOphus. Musculoelastic tissue at the caudal end Of the tract is virtually absent in Phasianus, Gallus and ChrysolOphus, but prominent in P239, Musculoelastic tissue spans a greater distance between the femoral and pelvic tracts (lateral pelvic apterium) in Phasianus, ChrysolOphus and 2319 than it does in Gallus. In all forms the musculoelastic sheet spanning the crural apterium is delicate but is well developed antero- ventrally. Crural Tract Description for Phasianus (Figures 16 and 17).--The crural tract covers the entire surface of the lower leg (Figure 6). With reference to a mid-dorsal longitudinal line, muscle and follicle rows course anterodorsally and posterodorsally. At the gross level, muscle rows are thick- est and about equally deve10ped on the anterior and posterior surface, moderately distinct on the lateral surface and faintly distinct on the medial surface. Quadrilaterals and muscle rows are indistinct, vertically, in the mid- region of the lateral surface (Figure 16). This pattern was also found in two other preparations. Muscle rows are moderately deve10ped at the ankle on the lateral surface, but not on the medial surface. Muscles end abruptly at the 151 commencement of scales covering the proximal end of the tarsometatarsus. At the subgross level thin bundles of ribbon-like double elevators and single depressors are present on the anterior surface. On the posterior surface muscle rows con- sist of double elevators and double depressors. In both . regions the depressors are slightly more develOped than the ( erectors. Interdigitation of muscle fibers accompanied by some tendinous anastomoses is characteristic of both regions. r» On the medial surface follicles are spaced further apart (Figure 6). Musculature is least developed in this region of the tract. Muscle rows are often indistinct at the gross level. Sometimes only anterodorsal muscle rows are formed and a pattern of quadrilaterals is not evident (Figure 17). Extremely thin depressors and elevators anastomose with each other by tendons mid-way between the follicles. Other fine muscle fibers radiate from different levels of the follicle and terminate within the dermis without linking to adjacent follicles. Longitudinal and transverse diagonals are present within the tract but are indistinct and do not form a continuous pattern. Retractors are most commonly found at the bulb. Comparison.--The pattern, degree of deve10pment and the arrangement of the feather muscles of the crural tract in Gallus and ChrysolOphus are similar to that of Phasianus. I 'L o‘u—Hsgc flagev -"£I'-'-i-n ‘ in». ' . l I 152 Figure 16.-~External View of the left crural tract of Phasianus colchicus showing the arrangement of the feather muscles and orientation of the follicles. A lhm drawn between AA' represents the anterior surface, behmmn PP' the posterior surface. Refer to Figure 15 for techniques in making the drawing. Bouin fixation, unstained and partially cleared. 155 ICM Figure 16 O v .. r _— -”-_ P \‘W *1- 154 Figure 17.--Internal view showing the arrangement and attachment of feather muscles to four follicles in the mid-region of the medial surface of the left crural tract of Phasianus colchicus. Refer to Figure 15 for techniques in making the drawing. Bouin fixation, unstained and partially cleared. dorsol posterior 155 Figure 17 Anterodorsal Muscles lodiol Muscles 0.2CNl 156 Musculature is least deve10ped in 2222, Arrangement of the muscles into rows could not be distinguished at the gross level. At the subgross level a pattern of closed quadrilaterals is present on the lateral, anterior and posterior surfaces. Muscle rows course antero- and postero- dorsally. These rows are characterized by numerous (4 to 6) thin, flat, loosely arranged bands of muscle. The most prominent features are the extensive amount of tendons and the anastomoses of muscle fibers mid-way between the follicles of all rows. Distinction between elevators and depressors is difficult. This pattern, reduced in deve10p- ment, is also present on the medial surface where there is a greater number of muscle fibers than on the lateral sur- face. Most of them are radial muscles of semiplumes. Lateral BodyATract Description for Phasianus (Figure 18).--The lateral body tract is wedge-shaped with the apex pointing posteroventrally toward the lateral border of the pectoral tract (Figure 6). Follicles are arranged anteroposteriorly into rows with 2 to 4 follicles in each row. Muscle rows course ventrally, ‘posteroventrally and longitudinally with reference to a mid— ventral longitudinal line (Figure 18). Closed quadri- laterals and triangles are present. Incomplete postero- ventral muscle rows connecting 5 to 5 follicles are dominant. These rows are comprised chiefly of depressors and retractors 157 Figure 18.--External view of the skin covering the latemfl surface of the body of Phasianus colchicus showing feaUmm muscles of the left lateral body tract. Refer to Figure 15 for techniques in making the drawing. Bouin fixation, unstained and partially cleared. Figure 18 159 which attach tangently at the neck of the follicle. Musculo- elastic tissue is absent in the lateral body apterium except at the narrow apex of the lateral body tract where a few scattered fibers unite with the muscles of follicles at the lateral border of the pectoral tract. 3 -.-_“b_" Comparison.--The shape of the tract is similar in all forms. In general, the tract is characterized by weak _ c—.'4- .- musculature seldom arranged into rows. This is especially true for Pavo where radial muscles predominate. Humeral Tract Description for Phasianus (Figures 19 and 22).--This is a rectangular tract narrowing and curving medially at the anterior end. Follicles are arranged close together in ‘posteromedial rows across the tract. The pattern of ‘pterylosis suggests that two follicles in adjacent postero- Inedial rows form the anterior and posterior boundaries for square quadrilaterals (Figure 8). However, a different pitmure is obtained when the pattern of the feather muscles is examined (Figure 22). 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EEV OEDHO> oaomDE mo cofluMHum> in m mqmdfi 167 Jillfl‘. . . t...sllfl1.ll . .stiIllr'Va Nmsm.m amam.n nosossson nnoEHoooo mossoss nos oonuncmoz moma.o ammo.o a omom.o a ason.o m as.o om sens samm.s asas.m ms memo.m o aoss.s s mm.s mm on: mmmm.m omoo.m as moma.m o soss.s m ao.m mo mus mmaa.m sema.m ms mmoo.m m moon.s m as.m me an: omms.m csom.m ms smoo.m m omom.s m mo.m me on: moso.m amom.m as aoos.a o omms.s m mm.m ms mus mono.m smm>.m as oasm.a o mmma.s m oa.m om suz ossm.m amss.o as oaam.a o mmom.s o so.m mm o mmon.m smmo.s as mama.m o mmas.m m mm.a mm sus somo.s snos.o ms mamm.m m onmm.m m ms.n ass mus mooa.s osmo.o os cams.a o oaom.m o oo.o sms mus onsa.s soso.o as aosn.n o mmoo.m o os.s Nos ale NOON..O Ommw.fi m HMNN.O N OdOfi..fi H «mam Nd.“ *mld All furl» Iain :IHHHJI. Elbfax. _ v w . 168 Figure 20.—~Relationship of muscle volume to (A) feather weight and (B) feather length of contour feathers in the right pectoral tract of Phasianus colchicus. "a" repre- sents a complete chevron row 5 follicle rows caudal to the under-marginal coverts of the prepatagium; "p" a complete chevron row 5 rows caudal to "a." L = lateral follicles, M = medial follicles. Black symbols refer to length or weight of feathers and Open symbols to volume of muscles. 169 In: a... a... .4 I. l. smEEo mEDJO> muons: 8 6 4 2 _ _ A _ a p a p ---OVOL. --Av0L. —'. WT. ——‘ WT. 2 6543 n02: PIG-m; KUIF mJOmDE O 8 6 4 2 —. LEN. a p —_‘ LEN. a _ _ s s s iZOIr- o o O. zo— AE Eu IPOZWJ ENIPHH0suumm pom pocsmumcs .cosumxsm assom .mcsBMHO mnu mcstE as mosvscnoou mom ms musmsm Ou Hmmmm .mDuOfim mammOsOmNHSU mama m Eoum .c305m you mum poms» sousmmo may mo mososssom Hosumuc¢ .csxm on» mo mumpcson uso why mucomoumou mass Lump one .uomuu smusmmo smuoumH mnu mo OHDuMHSOmoE Hosummm Hmsosm Iuomsm osmossmp was mo omusoo exp Hmm>on ou ©o>OEmH coon mm: mnouumuuoum ommo mnu mo COHuoom d .AwHHMmHOp mssmos>uou Humcawm Houomuuoua .52 no moHOmDE Houomuuoum ommo map mo ucmfiomcmunm may mCHBOzm mumzummm mmmo may mo mmaosssom pcm mcscmmo Hmm smcnmuxw unmsu mnp cmmBqu asxm may mo 3OH> accumuCHII.om muomsm 201 om ousmsm ch _mu_amo EU To so .32 o _o ___o.._ co_touc< ommzasmo msosumsuoea one Ilk II o , .oo com wa wt.‘ 1. f. It n-ull 202 Figure 27.--Dissection of feather muscles associated with one of the outermost follicles of the left lateral cape of ChrysolOphus pictus. Viewed laterally from the internal surface. Attachment of retractors and protractors is at the neck end of the follicle. Protractors (= MM, protracfln pennati cervicalis dorsalis). 205 Depressors Retractors posterior Figure 27 2rnm Erectors Protractors .1? .. -:-' rm: : . lar-"zap 204 tightening is a prerequisite to contraction of the erectors. My third hypothesis is that M, protractor pennati cervicalis dorsalis alone functions to move the feathers to a display position. In this theory it is assumed that the bulb end of the follicle acts as the fulcrum. The action of the M, protractor pennati cervicalis dorsalis was deduced from the following experiment. Unilater- al transections of the skin were made in 4 anesthetized male Golden Pheasants. A longitudinal incision was made between the ear and the cape severing M, protractor pennati cervi- calis dorsalis. Care was taken not to cut the underlying cranial attachment of M, cucullaris pars cranialis. The wound was sutured and after recovery overnight males were resubmitted to hens. Males did not perform courtship diSplays until two days after the Operation. During display feather movement was drastically reduced on the Operated side, while feathers of the control side were fully extended. Positioning of the feathers on the Operated side reached 1/4 the maximum height after 6 to 7 days and full extension was attained after 11 to 12 days. These results strongly suggest that neither M, cucullaris pars cranialis nor the erector muscles of the cape are re- sponsible for extension of the feathers during display. Rather, it appears that the display position of the cape feathers results from the contraction of M, protractor pennati 205 cervicalis dorsalis. The prOposed action of the cape pro- tractors is illustrated in Figure 28. The above evidence negates the first hypothesis. The second does not seem feasible. It seems that the third hypothesis which presupposes a third class lever system best explains movement of the cape feathers in the courtship display of Chrysolgphus. This is further supported by the presence of strong retractors at the neck in the postero- dorsal and transverse rows. It appears that contraction of these muscles would return cape feathers back to a nondis- play position. Eng,--Musculature of the dorsal cervical tract is least deve10ped in Pavo cristatus. The pattern and extent of deve10pment are similar in males and females. Flat bundles of muscle which link adjacent feathers in the domi- nant anterodorsal and posterodorsal rows produce diamond- shaped quadrilaterals. A few delicate longitudinal muscles may be present but in general they are absent from the tract. Unlike the chicken and the Ring-necked Pheasant, there is no distinct junction between the dorsal cervical and interscapu- lar tracts. In this regard, the pattern is similar to that described by Lucas and Stettenheim (unpublished) for the turkey. Interscapular tract Description for Phasianus (Figures 22, 29 and 50).--The junction of the dorsal cervical and interscapular tracts has {a 206 Figure 28.--Schematic representation of the course of the protractor muscles (= Mm, protractor pennati cervicalis dorsalis) and the movement of one cape feather from a non- display position (solid outline) to a display position (dashed outline). Male Chrysolophus amherstiae. 207 External Figure 28 Eiar 0:)erfir1g Protractors 208 been discussed previously. The interscapular tract differs from the dorsal cervical tract in having different muscle rows which are dominant and being much narrower in width (Figure 22). The interscapular tract is uniform in width throughout its length. In the anterior region muscle rows course principally posterodorsally and anterodorsally, the latter being more dominant. The anterodorsal rows correspond in direction to the chevron-shaped arrangement of the follicles. The latter is best illustrated in Figure 29. Dominance of the anterodorsal rows diminishes at the mid-dorsal line. Laterally these muscle rows are less deve10ped and are di- rected posterodorsally (Figure 22). Longitudinal muscles are present but are not arranged into distinct rows except lateral to the interscapular apterium. A dissection of the muscles associated with several follicles of the mid-region Of the interscapular tract of Phasianus shows that muscle bundles are well deve10ped (Figure 50). In the anterodorsal rows, where follicles are close together, a stout depressor-retractor muscle is present. This passes through 2 band-like erectors which generally attach tangentially to the neck end of the follicle. Delicate single or double retractors at the bulb end may act to Spread the feathers. Erectors and depressors are flat bands in the posterodorsal and longitudinal rows. The interscapular tract of Phasianus is characrerized by the presence of a median dorsal apterium about 5 209 Figure 29.-—External view Of part of the interscapular'trmx of male Phasianus colchicus showing the gross pattern of 8m feather muscles. Musculature Of the anterodorsal rows is not illustrated in order to show the pattern of follicle arrangement. Follicles of a chevron arm are numbered conmr cutively, laterally, from the apical feather (0). Dermal muscles have been removed. Musculoelastic tissue and muscles of the radial type found at the lateral borders of the tract are not shown. Refer to Figure 15 for techniques in making the drawing. t t (In M " L ‘1‘. -3&.'1 tam" m; 211 Figure 50.--Dissection of feather muscles associated with 7 medial follicles of 2 left chevron arms of the inter- scapular tract. Internal view. From a male Phasianus colchicus. Refer to Figure 29 for the method in numberhm the follicles. 212 Retractors ot bulb De press or—letroctor anterior loterol Elevotors De pressors Elevo tors Figure 50 J . . Jim’s-3' ;-.. "amt—.111”? 215 centimeters long in adults. I found a similar apterium in a day old chick. In the description of pterylosis the posterior end of this apterium was used to delimit the junction of the interscapular and dorsal tracts (Figure 8). In most of the specimens of Phasianus I examined the apter- ium was restricted to the interscapular tract. However, in one preparation the apterium extended into the dorsal tract (Figure 22). One or several centrally located follicles may be present anteriorly in the apterium. Musculoelastic tissue is absent within the apterium but delicate depressors, erectors or retractors cross the apterium in such a way as to connect the lateral arms Of the gapped chevron-shaped follicle rows. The anterior boundary of the interscapular apterium is just posterior to the insertion of the Clavicular component of M, cucullaris pars cervicalis and M, latissimus dorsi pars dorsocutaneus (Figure 9). Musculature is well develOped lateral to the interscapular apterium. Rows course chiefly anterodorsally and longitudinally. ‘ Comparison.--The gross pattern and arrangement of feather muscles of the interscapular tract are most similar in Phasianus and ChrysolOphus. Musculature appeared to be slightly less develOped in Pavo, slightly stronger in Gallus. No significant differences were noted in muscle deve10pment between males and females of the same species. Greatest differences in muscle arrangement seem related to differences in patterns of pterylosis. The interscapular 214 apterium was absent in Egyg, present in ChrysolOphus and variable in Gallus. In one preparation of Gallus in which the apterium was absent, longitudinal muscle rows were more dominant than the anterodorsal rows. Also, longitudinal rows connected adjacent apical follicles, a feature not found in the anterior region of the tract (Figure 29). However, musculature associated with the apical follicles was generally weak. Mid-dorsal musculature was further reduced in another preparation. Small longitudinal muscles connected apical follicles but anterodorsal rows were absent. In a third preparation of Gallus apical feathers were absent and thin delicate muscles crossed the apterium in a pattern similar to that described previously for Phasianus. In all instances the apterium or area Of reduction of mid-dorsal musculature was located in a 5 centimeter long region at the posterior end of the interscapular tract and corresponded in length and location to the apterium found in Phasianus and ChrysolOphus. The junction of the dorsal cervical and the interscapu- lar tracts in ChrysolOphus is similar to that of Phasianus and Gallus. But the change in dominant rows from postero- dorsal and longitudinal to anterodorsal appears to be more gradual in ChrysolOphus (compare Figure 25 with Figure 22). Dorsal and pelvic tracts Description for ghasianus (Figure 22).--The dorsal tract can be differentiated from the interscapular tract by 215 the fact that it is wider (Figure 22). However, it is con- tinuous caudally with the pelvic tract and there is no dis- tinct separation between the two. For this reason in the description on pterylosis an arbitrary line was drawn be- tween the trochanters of the two femurs. Collectively, both tracts are subsequently referred to as the dorsopelvic tract. Muscle rows are directed anterodorsally, posterodorsally and longitudinally. An anterodorsal muscle row is composed of muscles which connect follicles of a chevron arm. Posterodorsal and longitudinal rows connect adjacent chevrons. .Anterodorsal rows are dominant throughout the dorSOpelvic tnract. In the mid-region, intersection of dominant anterodorsal arbd.posterodorsal muscle rows produces a pattern of diamond- straped quadrilaterals. A different pattern is formed lateral- ly'. Parallelograms result from the intersection of antero-