THE FROG 69 



The adductor longus is a narrow thin muscle lying along 

 the abductor side of the sartorius, and more or less hidden 

 by it. Divide the sartorius about its middle and reflect its 

 parts; this will expose the adductor longus, whose fibers 

 mingle with those of the adductor magnus along its distal 

 third. 



The gracilis major or rectus internus major, a power- 

 ful muscle on the adductor side of the adductor magnus. 

 About its middle it is crossed by an oblique tendinous in- 

 scription or tendinous intersection. (The tendinous in- 

 scriptions of the limb muscles are homologous with those of 

 the abdomen, which are segmentally arranged an inheri- 

 tance from the metameric condition of the body muscles in 

 the fishes and the tailed amphibians.) 



The gracilis minor or rectus internus minor is a narrow 

 flat muscle running along the adductor surface of the thigh 

 and partly covering the gracilis major. It is sometimes re- 

 moved with the skin. 



(&) Superficial muscles of the postaxial side. This 

 side is dorsal when the thigh is adducted and the leg ex- 

 tended. 



The triceps femoris, a very large muscle occupying the 

 entire abductor surface of the thigh. It originates by three 

 heads, anterior, middle and posterior; the anterior head lies 

 partly on the preaxial surface. 



The semimembranosus, a large muscle lying along the 

 adductor surface. There is an oblique tendinous inscription 

 running along this muscle, as in the gracilis major. 



The ileo-fibularis, a slender muscle lying between the tri- 

 ceps femoris and the semimembranosus. 



The iliacus externus arises far up on the crest of the 



