4-58 SIR WILLIAM JARDINE ON MONKEYS, 



his bent fists upon the ground and drawing his body between his arms.' The nar- 

 rowness of the pelvis, and the short neck of the femur, forming an acute angle with 

 the spine, also render the erect position impossible for any time and always irksome, 

 which is farther confirmed by the weakness of the muscles. The glutei are scarcely 

 visible, and the calves are very weak. 



" The extensors of the knee are much stronger in the human subject than in 

 other mammalia, as their operation of extending the thigh forwards on the leg 

 forms a very essential part in the human mode of progression. The flexors of the 

 knee are, on the contrary, stronger in animals, and are inserted so much lower 

 down, even in the monkeys, that the cord which they form keeps the knee habitu- 

 ally bent, and almost prevents the perfect extension of the leg on the thigh. < The 

 motion of the knee-joint in the black orang was free backwards, but the animal 

 does not seem capable of perfect extension of this joint from the contraction of the 

 posterior muscles of the limb.' 



" The most remarkable muscle about the top of the thigh has not been noticed 

 by Tyson, Camper, Cuvier, or the older anatomists. It is a flat triangular muscle, 

 arising from the whole anterior edge of the ileum to within half an inch of the ace- 

 tabu] um, and is inserted just below the fore-part of the great trochanter, between 

 the head of the crurales and vastus externus, a little below the origin of the former. 

 It is thin and fleshy through its whole extent, except where it is inserted by a very 

 short flattened tendon. At its upper part it is united by cellular substance to the 

 iliacus externus. The action of this muscle appears to be intended to assist in 

 climbing. On this account we intend to name it scandens, or musculus scansorius ; 

 and we are disposed to regard it as one of the principal peculiarities in Simia 

 satyrus." DR. TRAIL. Account of Slack Orang. Wern. Soc. Trans. Vol. iii. 

 p, 29. 



" Continuing the organisation of the lower extremity, we shall now examine the 

 foot. In man the whole surface of the tarsus, metatarsus, and toes rests upon the 

 ground, and the os calcis forms a right angle with the leg. In the orangs this bone 

 begins to form an acute angle with the limb, and consequently does not rest upon 

 the ground. The sole of the foot becomes narrower ; and in all the attempts at 

 erect progression exhibited by the orangs which have been shown in this country 

 the foot was never observed to rest on its outer edge. The plantaris muscle also, 

 which is very fleshy among quadrumanous animals, instead of terminating, as it 

 does in man, by insertion in the os calcis, passes over that bone into the sole, and is 

 there connected with the plantar aponeurosis ; an arrangement incompatible with 

 the erect attitude, as the tendon would be compressed and its action impeded if the 

 heel rested on the ground. But the most marked peculiarity in the foot, and one 

 which is instantly perceived, is the great length of the phalanges or toes, and the 

 position of the great toe, which is placed nearly in a line with the ankle, and does 

 not reach at the nail within an inch of the first metatarsal joint, having the appear- 

 ance of a thumb and hand, whose office it in reality performs. Nor is the internal 

 conformation less remarkable ; the whole arrangement of muscles is much nearer 

 to that of a hand ; but the thumbs of both the fore and hind extremities have no 

 separate flexor lorigus (long flexor), but receive tendons from the flexors of the 

 fingers. ' Hence the thumbs in these animals will generally be bent together with 

 the other fingers ; and they are less capable of those actions in which the motion of 



