CHAP. IV] THE GENERAL ANATOMY OF GORILLA 



185 



Long head 

 Short head 



sacral portion is the largest, and the ischial part has been described 

 as a separate muscle, the M. ischio-femoralis (Duvernoy). The 

 M. scansorius is said to be merged in the M. gluteus minimus. 



The M. biceps femoris commonly 

 consists of two distinct portions, as 

 in Chimpanzees (cf. Fig. 122). 



The adductors of the thigh com- 

 prise four muscles arranged in the 

 following manner (Deniker). 



The M. adductor primus corre- 

 sponds to the M. adductor longus of 

 human anatomy, and is attached to 

 the horizontal ramus of the Os pubis 

 and not to the body of that bone, as 

 in Man. The M. adductor secundus 



corresponds to the M. adductor brevis 

 n -at i • i j , ,i r j Fig. 122. Dissection of the outer 



of Man, and is attached to the body side f the thigh of an adult female 



of the Os pubis. The M. adductor Chimpanzee, shewing the two heads 



of the M. biceps: also the great 

 tertlUS (corresponding to the upper sciatic nerve and its division. 



part of the M. adductor magnus) of 



Man is attached to the descending ramus of the pubis and also to 



the linea aspera of the femur. It sends a slip to the M. adductor 



secundus. 



Lastly, there is the M. ischio-condyleus, which corresponds to 

 the condylar portion of the M. adductor magnus of Man. The 

 separate existence of this ischio-condylar muscle is very charac- 

 teristic of Cercopithecidae and Simiidae. It encroaches at its 

 insertion upon the popliteal area of the femur. 



The M. gracilis is very wide throughout, and at its insertion it 

 extends into the deep fascia of the leg and thus to the lower part 

 of the tibia. 



Of the M. quadriceps extensor cruris, the component M. rectus 

 may present a bicipital conformation, as in Man. 



The M. psoas minor is variable in its occurrence, being rather 

 more frequently absent (60%) than present (40;/) (Keith). 



The M. soleus is of interest, inasmuch as it has been found in 

 the Gorilla with an occasional tibial origin. Otherwise it follows 

 the rule for Cercopithecidae, and has only a fibular origin. 



