510 



THE VERTEBRATE SKELETON. 



are well developed, the pollex being the smallest. The carpal 

 bones retain their primitive arrangement, the magnum articu- 



FIG. 107. LEFT MANUS OF 



A. Coryphodon hamatus. (After MAKSH.) xi. 



B. Phenacodus primaevus. (After COPE. ) x J . 



C. Procavia (Dendrohyrax) arboreus. (After VON ZITTEL.) 



1. scaphoid. 



2. lunar. 



3. cuneiform. 



4. trapezium. 



5. trapezoid. 



6. magnum. 



7. unciform. 



8. centrale. 



9. pisiform. 



I, II, III, IV, V. first, second, 

 third, fourth and fifth 

 digits respectively. 



lating with the lunar and not with the scaphoid. There is no 

 separate centrale. 



In the HYRACOIDEA (fig. 107, C) the manus is very similar 

 to that in Phenacodus, but a centrale is present and the pollex 

 is much reduced. 



The manus of the AMBLYPODA, such as Coryphodon (fig. 

 107, A) and Uintatherium, is short and broad, with five well- 



