1874.] MYOLOGY OF PHRYNOSOMA. 77 



with the epicoracoid and prsecoracoid, which might well represent 

 the supraspinous fossa ; the infraspinatus arises from the surface of 

 the scapula proper, which might be taken to represent the infra- 

 spinous fossa, while the teres minor arises from the edge of the bone ; 

 all these facts appear to me to point in the same direction. In a 

 paper entitled " On the homologies of certain muscles connected 

 with the shoulder-joint"*, Prof. Rolleston points out that the epi- 

 coraco-humeral [my supraspinatus] is homologous with the sub- 

 clavius. In a memoir which was published in the same volume of 

 the Transactions of the Linnean Society, " On the Myology of the 

 Orycteropus capensis," Mr. Galton showed that the subclavius in 

 that animal has, among other insertions, one into the fascia covering 

 the supraspinatus ; and, seeing that the nerve which in anthropo- 

 tomy supplies the supraspinatus arises from the same cord of the 

 brachial plexus as, and close to, the one which supplies the sub- 

 clavius, we have a body of evidence to show that, although the 

 ingenious line of argument adopted by Prof. Rolleston satisfactorily 

 proves that the muscle in question represents the subclavius, yet 

 it is quite possible that it is partly homologous with the supra- 

 spinatus also, viz. in its insertion. 



Subscapulars (fig. 2, S.) arises in two portions — one from the 

 whole of the inner surface of the coracoid (with the exception of a 

 small part on the inner edge) and from a small portion of the scapula 

 adjacent, the other from the surface of the scapula close to its junc- 

 tion with the suprascapula. These two sections join together at 

 rather more than a right angle, and are inserted into the inner side 

 of the head of the humerus and into the capsular ligament of the 

 shoulder-joint. 



Deltoid (figs. 1 & 3, D.) arises from the ventral half of the 

 clavicle and from the interclavicle, and is inserted into the outer 

 side of the humerus just beyond the head of that bone. This ap- 

 pears to represent the clavicular portion only of the muscle, and the 

 part marked Dl by Mr. Mivart in Iguana. 



Peetoralis major (fig. 1, P.) has the usual arrangement. 



Biceps (fig. I, B) arises, as usual, by a broad musculotendinous 

 origin from about the anterior and inner third of the outer surface 

 of the coracoid ; it passes down the arm and is inserted by a broad 

 tendon into the contiguous surfaces of both the radius and ulna in 

 conjunction with the 



Brachialis anticus (figs. 1 & 3, B.A.), which arises from the 

 outer surface of the humerus for about two-thirds of its length, 

 commencing just beyond and outside the insertion of the peetoralis 

 major ; its insertion joins that of the biceps. 



Coraco-brachialis longus (figs. 1 & 2, C.B. I.) arises narrow and 

 fleshy from the posterior point of the coracoid, and is inserted into 

 about the distal third of the inner side of the humerus and into the 

 ventral surface of the inner condyle. 



Coraco-brachialis brevis (fig. 1, C.Br.), short and broad, arises 

 from the whole surface of the coracoid ventrad of the coracoid 

 * Trans. Linn. Soc. vol. xsvi. pt. 3. 



