SKELETON OE BIMANA. 



55S 



362 



The heel in the Gorilla makes a more decided backward projection 

 than in the Chimpanzee ; the heelbone is relatively thicker, deeper, 

 more expanded vertically at its hind end, besides being fully as 

 long as in the Chimpanzee. Among all the tailless Apes the cal- 

 caneum in the Siamang and other Gibbons least resembles in its 

 shape or proportional size that of Man. Although the foot be 

 articulated to the leo- with a slio;ht inversion of the sole it is more 

 nearly plantigrade in the Gorilla than in the Chimpanzee. The 

 Orang departs far, and the Gibbons farther, from the Human type 

 in the inverted position of the foot. The great toe which forms 

 the fulcrum in standing or walking is perhaps the most charac- 

 teristic peculiarity in the Human structure ; it is that modification 

 which differentiates the foot from the hand, and gives the cha- 

 racter to his order (Bima?ia). In the degree of its approach to 

 this developement of the hallux the quadrumanous animal makes a 

 true step in affinity to Man. The Orang-utan and the Siamang, 

 tried by this test, descend far and 

 abruptly below the Chimpanzee 

 and Gorilla in the scale. In 

 the Orang the hallux does not 

 reach to the end of the metacarpal 

 of the second toe ; in the Chim- 

 panzee and Gorilla it reaches to 

 the end of the first phalanx of 

 the second toe : but in the Gorilla 

 the hallux is thicker and stronger 

 than in the Chimpanzee. In both, 

 however, it is a true thumb by 

 position, diverging from the other 

 toes, in the Gorilla, at an angle of 

 60 degrees from the axis of the 

 foot. 



§191. Skeleton of Bimana. — 

 The parts of the bony frame of 

 Man, fig. 183, are co-ordinated 

 for station and locomotion on and 

 by the pelvic limbs, which sus- 

 tain the trunk erect, and liberate 

 the pectoral, now the upper limbs, 

 for other uses. 



A, Vertebral Column. — This is disposed in an undulating series 

 of opposite curves, fig. 362 ; backward in the chest and sacrum, 

 forward in the loins and neck. The vertebra) which rest on the 



Diagram of the curves of the vertoJ)raI column, as 

 supported on one leg, in the act of walking. 



