B I R 



B I R 



tTie fpace between the ribs and the fternum. This miifcle, 

 like the preceding, dimininies the abdomen, and dilates the 

 anterior part of the thorax. 



The third layer anfwers to the tranfverfalis aitfomir:!s. It 

 proceeds from the ofleous margin of the abdomen to the 

 middle line, where it meets its fellow. They confill of fe- 

 parate fafcicnli at the fuperior part ; ai;d the fibres are col- 

 le»!^td round a point in the centre, where the yolk pafied 

 into the belly of the chick. 



There is a very t'lin (lip of mnfcle, which crofTes the lowed 

 part of the belly ; it is fituated fuperficially, and lies ovtr fe- 

 veral of the mufelcs of the tail. In the goo/i it arifes from 

 the ifchiuni, where that bone joins the pubis ; and in the 

 Jhiul it is Oiily attached by cellular membrane to the furface 

 of the mufcles of the thigh. It is inferttd, in both cafes, 

 on the fide of the aniis, which it feems dcligned to dilate. 



We have obferved in the fo'w! two very flender fafciculi 

 of mufcle to defcend from the fide of the reftum, one to the 

 ligament fupporting the quills of the tail, the other to the 

 infide of the pelvis. They are both probably intended to 

 produce the everfion of the iiiteftine d'jring coition. 



The nnifclts belonging to the -wing do not differ in their 

 arrangement and ftnifture from thofe of the anterior extre- 

 mity of mnnnmaha fo much as might be fuppofed, confider- 

 ing how little thele members refemblt each other in their 

 funftions. 



The lati/Jimiis dorft arifes only from the fpines of the dor- 

 fal vertebrae ; it refembles, however, the mufcle of the fame 

 name in mammalia. 



A mufcle, analogous to the inferior portion of the trape- 

 zius, is obferved at the (houlder. It comes from the fpi- 

 nous procelTes of the three laft cervical and all the dorfal 

 vertebrae, and is inferted into the inner and back part of the 

 fork and potterior edge of the fcapula. We have not 

 perceived the diftinftion of this mufcle into two parts on 

 the fhoulder, as dated by Cuvier. 



The_/Jrra/uj major anlicus is only inferted into the point of 

 the fcapula. This mulcle has been called by Vic d'Azir, 

 the fubj'capular'is. 



The cojlo-fcapularis of Vic d'Azir goes from the fird ribs to 

 the neck of the fcapula. It appears to be analogous to the 

 pelioralh minor of the human fubjcft. 



The rhomlo'iilcs is not divifible into major and minor. It 

 arifes, as ufual, from the fpine, and is inferttd in the pode- 

 rior edge of the fcapula. 



A mufcle, analogous to h-vator fcapula, arifes by three 

 flips from the tranfverfe procefs of the laft cervical vertebra 

 and the firft and fecond ribs. It is inferted into the middle 

 of the fcapula, which it elevates and draws backwards. 

 The motions of the fcapula are necedaiily very limited 

 from its mode of connexion with the neighbouring bones ; 

 and its rotation is redrained by a ligament which joins the 

 point of the fcapula with the dorfal fpine. It is requifite 

 the bones of the fhoulder fhould be kept very fteady during 

 fliglit. 



There are three peftoral mufcles. 



'Y\\Q peBoralis maximus of Vic d'Azir might be called, with 

 more propriety, the deprejjor al<r magnus. It arifes from the 

 whole of the body and heel of the ilernum, except a certain 

 portion ot the anterior furface occupied by the next muf- 

 cle over which it lies, and from the fide of the fork and the 

 lad ribs, and is inferted into the fpine on the outfide of the 

 humerus, where it is connefted by ligament with the deltoid 

 mufcle. The peftoralis maximus has commonly more 

 ftrength than all the other mufcles of the body united, 

 which is required to accomplidi the deprefllon of the wing 

 In oppolitioa to the whole weight of the bird during flight. 



Th« ptBoraFts medius of Vic d'Azir might be called the 

 levator alx. It is affixed to the fore part of the body and 

 keel of the dernum, the fide of the clavicle, and the mem- 

 brane which fills the interfpace between that bone and the 

 fork. It fends its tendon over the head of the fcapula 

 through the pully formed by all the bones of the (hoi^lder, 

 to be inferted on the external tuberofity of the head of the 

 htimeri's. By means of the pulley it elevates the hume- 

 rus, and corfequently the wing ; and from occupying the 

 lower pnrt of the cheft, the weight is kept in the fituaiion 

 mod convenient for the bird during flglit. 



'The peiloralis minimus of Vic d'Azir, or dcprejfor ala: mi- 

 nor, arifes from a portion of the dernum behind the articu- 

 lation of the clavicle, and from the infide of the demal ex- 

 tremity of the clavicle. It is inferted under the head of the 

 humerus ; depreffes the wing, and brings it clofe to the 

 body. 



T\\tfubcla-vius^\s extended from the infide of the dernal 

 extremity of the clavicle to the adjoining part of the internal 

 furface of the dernum. It is impodible to conceive the 

 ufe of this mufcle, uulefs it be to ilrengthen the joint, 

 as its attachments are incapable of motion towards each 

 other. There are mufcles analogous, as much as the form 

 of the bones will perm.it, to X.\iefubfcapularis, teres major and 

 minor, fuprafpinalus, and infra fpinalus. 



Cuvier defcribcs two little mufcles which come from 

 the infide of the clavicle to the head of the humerus. 

 We have obferved a mufcle in the foiul which appears 

 to correfpond to one of thefe ; it arifes from the inner 

 furface of the clavicle, and its joint with the dernum, 

 paffes over the fird rib, and is affixed to the top of the 

 inner tubercle of the head of the humerus. It rotates 

 the wing inwards, when it has been fpread in flight. The 

 lottrr ed/e of this mufcle, and the infide of the teres major, 

 produce a mod delicate tendinous cord, or fibre, which dc- 

 fcends on the back of the upper arm, and is lod amonglt 

 the ligaments of the quills below the elbow. The effeft of 

 this, if any, is to bring the wing nearer the body, and per- 

 haps fpread the quills. 



The deltoides is fmall, and of two portions. One arifes 

 from the foik at the top of the diojlder, and fends a fmall 

 tendon to the aponeurotic expanfion of the fold of the wing. 

 This tendon, as it proce^ ds along the edge of the expanfion, 

 acquires exaftly the ftruCture and the elafticity of the liga- 

 mentum nucha ; it then becomes like common tendon, 

 pafies over the end of the radius, and is inferted into the 

 dyle of the metacarpal bone. It bends the fore arm, ex- 

 tends the hand, and, in confequence of the eladicity o£ 

 the tendon, contracts the foft part of the fold of the 

 v^ing. This portion of the deltoid has efcaped the obferva- 

 tion of Cuvier and other writers, although the ftrufture of 

 the tendon is one of the mod extraordinary circumdances in 

 the anatomy of birds. The rema'ning prrcion of the deltoid 

 is analogous to the fame mulcle of the l.uman fubjeft, and 

 brings the wing upv%'ards and backwards in flight. 



The mufcle which nprtftnts the bictps jlexor cubiti, takes 

 its origin from the end of the clavicle, where it joins the 

 fork ; and from the (harp tubercle of the humerus, which is 

 analogous to the coracoid proccfs, tlie chief part of the muf- 

 cle proceeds to be inferted into the infide of the neck of the 

 radius ; but as it dcfcends, a fmall portion goes off, and is 

 expanded in the fold of the wing, and attached to the outer 

 fide of the arm. This expat;fii)n of tendon correfponds to 

 the aponeurofis of the biceps mufcle of the human fubjeft ; 

 but indead of lying clofe to the fore arm, it is fpread out 

 and covered with the common integuments. 



The brachialis internus is very fmall, being only attached 



