The Gluteal and Femoral Muscles in a Marmoset. 175 



more anterior part of gluteus minimus according to Bischoff. 

 Huxley (13) stated that it was present in the Cynopithecini, 

 but was sometimes fused with minimus. 



Among Anthropoids it is present and distinct in the 

 chimpanzee and the orang (8). It arises from the dorsum 

 ilii between gluteus minimus and tensor fascia femoris, and. 

 is inserted into the anterior margin of the great trochanter, 

 close to the lower edge of the tendon of gluteus minimus. 

 Its attachments correspond fairly closely with those of the 

 muscle in Hapale. In Hylohates leuciscus (9) the scansorius 

 proper is absent, but there is present a small separate muscle 

 which arises from the anterior inferior spine of the ilium, 

 and is inserted into the great trochanter at its base. 



A scansorius is occasionally present in man, and appears 

 to be, as in the other mammals cited, a separation of the 

 anterior fibres of gluteus minimus. 



Pyriformis was a fairly large, distinct, and separate 

 muscle. It arose from the 1st, 2nd, and 3rd pieces of the 

 sacrum, from the ridges of bone between the anterior sacral 

 foramina, and from the pelvic surface of the sacrum external 

 to the foramina. The fibres converged to form a rounded 

 muscle which passed out through the great sciatic notch, 

 receiving as it did so a considerable accession of fibres from 

 the upper margin of the notch. 



It was inserted by a tendon into the very apex of the 

 great trochanter. 



It lay between the gluteus medius and the gluteus minimus. 



The nerve to pyriformis was derived mainly from the 

 last lumbar nerve and partly from the first sacral. 



In Midas rosalia (3) the pyriformis is distinct from other 

 muscles. Outside the Hapalidse it is connected in a greater 

 or less degree with the gluteus medius in almost all monkeys, 

 showing differences in the degree of fusion in closely related 

 animals, e.g., in Hylohates leuciscus it is only slightly fused, 

 in H. agilis almost completely fused. 



In man one occasionally finds more or less fusion between 

 the muscular part of pyriformis and the gluteus medius. 



Obturator internus arose from the pelvic surface of the 

 innominate bone and the obturator membrane. I was unable 



