viii.] THE MUSCLES. 341 



representative in man. Such a muscle is the femora-caudal 

 of Reptiles, Birds, and Tailed-Batrachians. This (e.g. in the 

 Iguana and Chameleon) arises beneath the caudal vertebrae, 

 and, though mainly inserted into the femur, sends on a deli- 

 cate tendon which, passing down, is inserted into the articular 

 cartilage between the femur and tibia. 



FIG. 306. MUSCLES OF EXTERNAL ASPECT OF LEG OF AN EAGLE 

 (A quilafucosa), 



i, sartorius ; 2, tensor vaginae femoris (?); 3, biceps; 4, semi-membranosus : 5, 

 levator coccygis ; 6, tibialis anticus ; 7, gastrocnemius. 



(After A. Milne-Edwards.} 



Glutens maximus. This muscle is of very exceptional size 

 in man, directly related as it is to his erect attitude. Never- 

 theless, it may be yet greater relatively in some quadrupeds 

 than it is in him, as e.g. in the Echidna, where it is double, 

 and where part passes from the sacral and coccygeal vertebras 

 downwards to the ankle, and represents that part of the 

 muscle which in man is inserted into the fascia lata, while 

 another portion with a similar origin is inserted into the 

 femur. The muscle exists in Birds and in Reptiles. In the 

 Chameleon (Fig. 311) it passes from the caudal vertebras to 

 the tendinous arch going from the posterior margin of the 

 ilium to the tuberosity of the so-called ischium. This muscle 

 may be inserted into the whole length of the femur, as in 

 the Seal. 



The gluteus medius is very often much thicker and larger 

 than the gluteus maximus. This is the case, e.g., in the Horse, 

 where it is twelve times as big as the maximus. It may arise 

 not only from the ilium but from the sacral and even from the 

 lumbar vertebral spines, as in the Echidna. The muscle ap- 

 pears to be almost a constant one, as it exists, well-developed, 



