168 Proceedings of the Royal Physical Society. 



XV. The Gluteal and Femoral Muscles, with their Nerve 

 Supply, in a Marmoset (Hapale jacchus).i By E. B. 

 Jamieson, M.B., Ch.B. 



(Received 14th March 1904; read 28th March 1904.) 



The descriptive terms which I have employed in this 

 paper are those which apply to man. From a comparative 

 anatomy point of view this is unjustifiable ; but those terms 

 are so commonly employed that it is difficult to get rid of 

 them in writing when one's views have been biassed by the 

 study of human anatomy. Cephalic, caudal, dorsal, and 

 ventral are the proper terms, but compound terms such as 

 cephalwards, which would require to be made use of in order 

 to be consistent, are clumsy, and the marmoset is not so 

 horizontal in its attitude that the application to its anatomy 

 of human descriptive terms cannot be readily understood. 



Throughout the paper I have, in connection with each 

 muscle, drawn attention to differences or resemblances in the 

 corresponding muscles or groups of muscles in certain other 

 Primates. What one would wish to find in such a review is 

 a progressive modification in the characters of muscles as 

 one ascends or descends the scale, but such modification is 

 strikingly absent in most cases. There is, however, an 

 approximation to progressive change of character in the 

 biceps flexor cruris and the quadriceps extensor cruris, which 

 in the Anthropoid apes have assumed man-like characters. 

 In the case of the latter muscle this is owing to the nearer 

 approach to the erect attitude. Against this there is the 

 gluteus maximus, which makes a sudden bound in its degree 

 of development from a thin, flat muscle in all the apes, 

 including Anthropoids, to the powerful, thick, fleshy muscle 

 found in man. 



In Hapale jacchits there is a great tendency to the sub- 

 division of muscles, and there is no muscle absent except the 

 short head of biceps. Occasional fusion is found between 

 adjacent muscles, but never to such a degree that separation 

 is not easy. 



^ The specimen on which this dissection was carried out was kindly placed 

 at my disposal by Dr 0. Charnock Bradley. 



