PliCULIAR TO MAN. l29 



thanner m progression : the gluteus magnus balances the 

 pelvis, while one leg is carried before the other, and 

 brought to the ground ; and the two others support the 

 trunk laterally, while the limb of the opposite side is in 

 the air. 



The gluteus magnus, which is the largest muscle of the 

 human body, is so small and insignificant in animals, that it 

 may be almost said not to exist. F. Cuvier observes of 

 the orang-utang, " Les fesses etoient presque nulles, ainsi 

 que les moUets *." Tyson indeed asserts, of the chim- 

 pans^, that " our pygmie had buttocks or nates, as we shall 

 see in the myology, but not so much as in man f .^* How- 

 ever, in his apparently accurate figure J there is no trace 

 of them. 



The extensors of the knee are much stronger in the hu- 

 man subject than in other mammalia, as their twofold 

 operation of extending the leg on the thigh, and of bring- 

 ing 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 iri the tibia, even in the 

 monkeys, than in the human subject, that the cord which 

 they form keeps the knee habitually bent, and almost pre- 

 vents the perfect extension of the leg on the thigh. Where 

 the thigh and leg thus form an angle, instead of being con- 

 tinued in a straight line, the support of the body on the 

 hind legs must be very insecure. 



The extensor muscles of tlife ankle joint, and chiefly 

 those which form the calf of the leg, are the principal 

 agents in progression. Hence man is particularly charac- 

 terized by the largeness of his calves ; and no animal 

 equals him in this respect. By elevating the os calcis, they 

 raise the whole body in the act of progression ; and, by ex- 

 tending the leg on the foot, they counteract that tendency 



* Annates du Museum^ v. 16. p. 47. The correctness of this remark is 

 fuHy verified by the orang-utang belonging to Mr. Abel. It has neither 

 buttocks nor calves. 



1r 4natnmy of a Pygmie, p. 1 4. | Fig. 2. 



K 



