266 MESSRS. B, C. A. WINDLE AND F. G. PAKSOXS ON fISiOV. 3, 



which comes off the sciatic outside the pelvis and below the point 

 of origin of the superior gluteal. 



Femoro-coccygeus {Agitator caudce). — This muscle can be made 

 out readily enough in most Ungulates by anyone who is famihar 

 with it and who appreciates the fact that it is the part of the 

 great muscular sheet which lies between the ectogluteus and 

 biceps. The origin is from the posterior sacral and anterior caudal 

 spines, and the insertion chiefly into the outer side of the patella ; 

 above and below this it blends with the fascia (see text-fig. 24). 

 As this muscle was not known by most of the older writers on 

 myology, its description is often included with that of the ecto- 

 gluteus or biceps. We believe that it is present in every Ungulate, 

 and that its attachments are very constant. It is supplied by 

 the same nerve as the ectogluteus. 



Tensor fascicB femoris. — As the femoro-coccygeus connects the 

 ectogluteus and biceps, so the muscle under consideration lies 

 between the ectogluteus and sartorius though it is often separated 

 by a good interval from the former. It rises from the iliac crest, 

 which of course is a short structure, and spreads out into a fan- 

 shaped muscular mass which usually becomes lost in the fascia lata 

 about the middle of the thigh. In the Elephant (79, 81, 84), 

 however, it runs two-thirds of the way down, while in the Tapir 

 (61, 62) it is fleshy as low as the outer side of the patella. Pater- 

 son and Dun have noticed in the Elephant (85), and Murie in the 

 Giraffe (33), that the fascia lata on the outer side of the thigh is 

 elastic. Its nerve-supply is the superior gluteal. 



Mesogluteus {Gluteus medius). — This muscle, as is usual in 

 mammals, is generally larger than the ectogluteus ; it rises from 

 the greater part of the gluteal surface of the ilium as far as the 

 margin of the great sciatic notch, as well as from the fascia cover- 

 ing the muscle. At its origin it is probably inseparably blended 

 with the pyriformis, at all events the latter can never be traced 

 to its human origin from the ventral side of the sacrum. The 

 insertion of the mesogluteus is into the great trochanter on its 

 outer and often also on its posterior surface. It is supplied by 

 the superior gluteal nerve in the Pig, Sheep, Antelope, and Horse, 

 but in the Harnessed Antelope (55) we also found a small twig 

 passing to it from the inferior gluteal. In the Perissodactyla the 

 muscle seems specially large, and its origin creeps along the fascia 

 lata covering it to the sheath of the erector spinse and the sacro- 

 iliac and sacro-sciatic ligaments, Meckel (VII.) says that in the 

 Horse it is twelve times as large as the ectogluteus, and it is also 

 very large in the Tapir. In the Pig and Hyrax it is relatively 

 much smaller, and Meckel describes it in the latter animal as 

 being absolutely smaller than the ectogluteus. In our specimen 

 of Hyrax (75) we do not feel justified in going as far as this, but 

 the muscle was certainly very thin in the middle. 



Entogluteus {Gluteus minmms). — This is also a large muscle, 

 but its exact attachments are difiicult to define owing to the fact 

 that it is often closely connected with the gluteus ventralis. We 



