342 



ELEMENTARY ANATOMY. 



[LESS. 



in Birds ; and a muscle seeming to represent it, passes from 

 the outside of the ilium to the femur in Reptiles and Batra- 

 chians. 



The gluteus minimus is, when distinct, almost if not quite 

 always smaller than the medius, with which it may be more 

 or less completely blended. 



The pyriformis may also be confounded with the gluteus 

 medius, as is the case in the Horse. 



Obturator internus. This may be wanting, as in the 

 Ornithorhynchus and Echidna. In the Three-toed Sloth 

 and Ant-eater it becomes a second obturator externus smaller 

 than the real one, having quitted its normal place. 



FIG. 307. INNER VIEW OF RIGHT HALF OF THE PELVIS OF HYRAX. 



Ot, obturator internus : Oter, obturator tertius ; PC, pubo-coccygeus ; C, coccy- 



geus; Gi, gemellus inferior; Am, adductor magnus. 



The gemelli may be wanting altogether, as in the Orni- 

 thorhynchus and Echidna. The gemellus inferior may be 

 almost as much developed as the obturator ; such, e.g., is the 

 case in the Camel. There may be but a single fleshy strip, 

 as in the Apteryx. 



The quadratus femoris is an almost constant muscle, 

 though varying as to size, shape, and direction. 



