REPTILES. 



draw the head inwardly, and to produce a fmall elevation of 

 the fhoulilers. The longus capitis arifcs from the third ver- 

 tebra of the back, and is infertcd by a flender tendon into 

 tlie cuneiform procefs of the occiput. The frogs have very 

 few of the mufcles of the head : mod of thofe which are in- 

 ferted in it are employed in moving the fuperior extremities, 

 or are proper to the vertebral column. The mufcle analo- 

 gous to the obliquus fuperior arifcs from the firil tranfverfe 

 proceflTes of the fpine, and is inferted into the fuperior part 

 of the occiput : its direAion is oblique from without inwards. 

 That which is analogous to the redtus capitis anticus minor, 

 arifcs from the tranfverfe procefs of the firll vertebra, and is 

 infertcd into the bafis of the cranium below the foramen mag- 

 num. Thefe are the only two mufcles proper to the head 

 in frogs : they are fimilar in the land falamander. 



Mufcles of the Shoulders. — In the frog (which has no 

 ribs) the fsrratus major has an extraordinary (hape, which 

 appears to be occafioned in part by the want of the cervical 

 vertebrse : it forms three diftinft mufcles. The firft arifes 

 from the occiput, near to the foramen magnum. It divides 

 into two bellies, which are inferted into the fuperior fpinal 

 angle of the fcapula ; one on the internal, and the other on 

 the external fide. The fecond proceeds from the fecond 

 tranfverfe procefs, and paffes under the dorfal portion of the 

 fcapula, towards its fpinal edge. Tlic thii'd proceeds from 

 the third tranfverfe procefs, and pad'es underneatii the pre- 

 ceding, keeping ftill nearer to the edge. There is befides 

 another mufcle proper to the fcapula, fituatcd upon its in- 

 ternal furface, between the two conflituent parts, which 

 make it appear broken. It appears to draw thefe two parts 

 clofer together, and by its contraftion renders the angle they 

 form with each other more acute. There is no mufcle 

 analogous to the peftoralis minor. The place of the levator, 

 or angularis fcapulae, is fupplied by a very confiderable 

 mufcle which rifes from the bafe of the occiput ; it becomes 

 perceptibly fmaller as it approaches the (lioulders, and is 

 inferted into the pofterior edge of the cartilaginous part of 

 the fcapula. The omo-hyoideus is long and thin ; it comes 

 from the great inferior horn of the os hyoides, and is in- 

 ferted under the neck of the fcapula. The trapezius is 

 wanting. The mufcle analogous to the rhomboides is very 

 thin. It arifes from the dorfal proced'es, and is inferted into 

 the fpinal edge of the fcapula. There is no fubclavius 

 mufcle. The fterno-maftoideus has only one belly, which 

 extends obhquely from the polterior part of the head, be- 

 hind the ears, to the neck of the ofleous part of the fcapula. 

 Its aftion is evidently that of pulling the fhoulder towards 

 the head, and raifing it up. We (hall defcribe the mufcles 

 of the tortoife feparately, as they differ confiderably from 

 thofe of other red-blooded animals. They are only three 

 in number. One of them, though very unlike the trapezius, 

 is fimilar in its ufe ; it rifes from the lower furface of the 

 back-fhell among the ribs, from the fecond to the fifth. It 

 js very thin, and paffes to the external margin of the third 

 bone of tlie fhoulder, which feems to correfpond with the 

 fcapula. A mufcle analogous to the levator fcapulse, is 

 inferted into the curve formed by the joint of the two firfl 

 bones of the fhoulder. It arifes by feven flcfhy heads from 

 the tranfverfe proceffes of the feven vertebras of the neck. 

 Another little long mufcle arifes from the inner furface of 

 the back-fhell near the fternal extremity of the firft rib, and 

 is inferted into the dorfal extremity of the firll bone of 

 the fhoulder. It is perhaps analogous to the cofto- 

 clavius. 



Mufcles of the Arm. — The peftoralis major of the frog is 

 corapofed of two portions, placed one above the other. 

 They produce two tendons which are inferted on each fide 



of the humeral groove. The latilfimus dorfi arifes from ti.e 

 inferior part of the back, where it is thin. It becomes 

 thicker, and is attached to the broad part of the fcapula, 

 which it entirely covers. It is inferted, by a flrong tendon, 

 into the internal furface of the humerus, above one-third of 

 its length from its fuperior end. In the frog there is neither 

 the fupra nor the infra-fpinatus. The fubfcapularis or coraco- 

 brachalis, (for the mufcle of which we now fpeak fupplies 

 the place of both,) arifes from the internal furface of the 

 fcapula, at its junction with the clavicle, and is inferted into 

 the interior part of the humerus about one-third from the 

 head. The deltoid is formed of three portions. The firit, 

 which is the longcfl, and very fleuder, proceeds from the 

 anterior part of the flernum. The fecond arifes from the 

 union of the clavicle with the fcapula, at the internal fur- 

 face, runs over the bone above the joint, then fends a thin 

 tendon to the firil in its paflage, and is partly inferted in the 

 linea afpera, and partly in tiie inferior portion of the hu- 

 merus. The third is diflinft ; it rifes partly from both the 

 fcapula and clavicle, and is infertcd into the fcapular extre- 

 mity of the humerus. The teres major and teres minor, are 

 wanting. Befides thefe mufcles, in which we difcover an 

 analogy to thofe of mammiferous animals, there is one which 

 arifes from the fecond tranfverfe branch of the iternum, and 

 is inferted into the inner edge of the groove of the humerus 

 by a broad tendon. It may be regarded as an afliitant ta 

 the peftoralis major. This conformation appears to prevail 

 in the falamander. « 



If the tortoife has fewer mufcles proper to the fhoulder 

 than common, it has an extraordinary number inferted 

 into the humerus. That which correfponds to the pec- 

 toralis major is compofed of five portions. Two are 

 fuperficial ; one arifes from the edge of the anterior part 

 of the breaft-plate, and proceeds to its infertion in the 

 lefier tubercle of the humerus. The other is much more 

 extcnfive : it rifes from a great part of the internal furface 

 of the breaft-plate, and is alfo inferted by a flat tendon ifi the 

 leffer tubercle of the humerus : but it is prolonged by a 

 fan-like aponeurofis, which extends over the inferior furface 

 of the arm, and even of the fore-arm. One of the three 

 deeper portions of the peftoralis major arifes from the greater 

 part of the fecond bone of the fhoulder, and is inferted into 

 the humerus, below its fcapular articulation ; another arifes 

 from the expanfion of the interofleous ligament, which 

 unites the fecond bone of the fhoulder to the third, and pro- 

 ceeds to join its tendon intimately with that of the preced- 

 ing portion. LalUy, the third, which is the moll deep- 

 feated of all, arifes from the fuperior furface of the third 

 bone of the fhoulder, or that which is next the back-fhell. 

 Its tendon is conjoined with thofe of the preceding. The 

 mufcle analogous to the deltoides is alfo compofed of two 

 portions ; one arifes from a ridge on the anterior part of the 

 breaft-plate ; the other, which is its acceffory, is placed more 

 deeply, and united to its correfponding mufcle. They are 

 inferted by one common tendon into the leffer tubercle of 

 the humerus, which they draw towards the neck in the aftion 

 of fwimming. There is another mufcle much deeper 

 feated, which feems likewife an affiftant to the deltoides. 

 It rifes from the dorfal extremity, and all the internal edge 

 of that bone of the fhoulder which correfponds with the 

 clavicle, and proceeds to be inferted into the humerus below 

 the leffer tuberofity. On the internal furface of the humerus, 

 we find a mufcle rifing from the loofe extremity of the 

 fternal face of the third bone of the fhoulder : it is inferted 

 in the humerus, about one-third from its lower end, by a 

 thin tendon. It bears fome relation to the fterno-radialis of 

 the frog, and performs the fama office. 



The 



