130 ON THE HOMOLOGIES OF CERTAIN MUSCLES 



of the obturator to the inner head of the pectineus. The branch 

 from the anterior crural, or from its internal cutaneous division, to 

 the outer head of the pectineus answers to the circumflex, whilst 

 the muscle, by having these two sources of nerve-supply, corresponds, 

 even curiously, with the two levatores humeri of the fowl, and the 

 glutei nerves and muscles are then left as homologues of the sub- 

 scapular, teres major, and latissimus dorsi. 



Thirdly, there can be little doubt that the coraco-brachiales, 

 superior and inferior, of Meckel (no. xvi. and xvii. of Schoepss), in 

 the bird correspond, not only to the adductores in the lower limb, 

 but also to the obturator internus and externus, arising as they do, 

 the former from the visceral, and the latter from the external 

 surface of the parts homologous with the points of origin of the 

 two obturatores. Now, close as is the relation between the tendons 

 of the smaller glutei and the obturatores at the external or larger 

 trochanter of the human femur, it is not at all more intimate than 

 that which subsists between the tendons of the coraco-brachiales 

 and those of the subscapularis and teres major on the lesser tube- 

 rosity, as represented by the crateriform rim of the pneumatic 

 foramen. If the superior coraco-brachialis, the origin of which is 

 described in my account of the muscles of the sparrow-hawk, be the 

 homologue of the obturator internus, it is difficult to deny the 

 homology of the subscapularis (with the tendon of which its tendon 

 fuses) with the gluteus medius, which holds so much the same 

 relation by its tendon to the obturator internus. 



Leaving now the subject of the homology of the subscapularis 

 and teres major with the glutei, I may refer to the nerve-supply of 

 the teres minor from the same nerve, the circumflex, which sup- 

 plies the deltoid, as showing that this muscle is really but a divari- 

 cation of the deltoid posteriorly, as a similar line of argument shows 

 the tensor fasciae femoris to be of the gluteus medius. The diffi- 

 culty, therefore, as to the nomenclature of the muscle, which in 

 Saurians and the monotrematous Echidna (see Mivart, ' Trans. Linn. 

 Soc' vol. xxv. p. 384, and 'Proc. Zool. Soc' June 1867, p. 778 ; 

 Stannius, 'Handbuch der Zootomie,' ii. p. 126) has been sometimes 

 called ' teres minor ' and sometimes ' a second part of the deltoid,' 

 may be met by saying that the posterior factor of the ' deltoid ' is 

 not, in these lower animals, differentiated into a superficially placed 

 ' deltoid ' and a deeper lying ' teres minor.' There is ordinarily no 



