69 



of the thigh. It appears rather to have reference to that structure 

 of the hip-joint which, in the Orang especially, from the absence of 

 the ligamentum teres, and in the Chimpanzee, from the yielding tex- 

 ture of that ligament, permits a greater extent of inward rotation 

 than can be accomplished in man. 



The sartorius is inserted lower down than in man. The rectus 

 cruris corresponds with the same muscle in the human subject ; but 

 the vasti and crurceus are much weaker and thinner, and are evi- 

 dently little adapted to support the thigh and trunk upon the tibia. 



The psoas magnus and iliacus internus are, on account of the form 

 of the pelvis, proportionally longer muscles than in man. Beneath 

 them exists a small distinct muscle passing from the fore part of the 

 ilium, over and attached to the capsule of the hip-joint, to be inserted 

 into the root of the trochanter minor. This muscle is not found in the 

 Chimpanzee. The pectineus is a narrower muscle than in man, and 

 gives off, in the Chimpanzee, a small slip, which is continued under 

 the femoral vessels and outwards to the origin of the sartorius. The 

 gracilis is a very powerful muscle in the Orang, but is comparatively 

 of less bulk in the Chimpanzee, in which it is inserted beneath the 

 sartorius. On this muscle being removed, a number of others appear 

 passing from the pelvis to the inner part of the thigh, among which 

 it is difficult to select those which are precisely analogous to the 

 muscles in the corresponding region of the human subject. Mr. 

 Owen, however, distinguished the adductor longus ; an accessory 

 adductor arising from the upper part of the symphysis pubis ; the 

 adductor brevis ; and the adductor magnus. 



The gastrocnemius preserves nearly a uniform thickness and 

 breadth throughout its course, and is continued fleshy down to the 

 os calcis: it has no sesamoid bone, as possessed by some monkeys 

 (e. g. Macacus cynomolgus, Lacep.), at either of its origins. The 

 soleus has only one origin, and is continued fleshy to the os calcis. 

 The tendon of the popliteus contains, behind the knee-joint, a fibro- 

 cartilaginous sesamoid body, which was noticed by Camper, who 

 states that it exists also in baboons, dogs, cats, &c. : this body, how- 

 ever, is not found in the Chimpanzee. 



In the Orang Utan there are some important differences in the 

 disposition of the flexors of the toes, as compared with the Chim- 

 panzee and inferior Si mice ; thus the muscle analogous to the flexor 

 longus pollicis pedis sends no tendon whatever to the thumb of the 

 foot, and its origin is extended above the knee-joint in a manner 

 analogous to the flexor sublimis in the upper extremity. It has two 

 origins, one from the outer condyle in common with the gastro- 

 cnemius internus, the other from the head of the fibula, and is con- 

 tinued down the posterior part of that bone and the interosseous 

 ligament to within an inch of the tarsus ; under which it passes 

 through abroad synovial sheath, deeper seated than, and external to, 

 the Jlexor longus digitorum ; becoming tendinous centrad, but con- 

 tinuing fleshy on the dermal aspect till it has reached the sole. 

 There it divides into two stout perforating tendons, which are in- 

 serted into the distal phalanges of the third and fourth toes. Im- 



