128 The American Naturalist. (February, 
functionally tridactyl, the outer toes being much shorter than 
the three median toes. Marsh describes the terminal pha- 
langes as intermediate between hoofs and claws, the extremi- 
ties are thin, slightly expanded, and apparently covered by 
thin nails. In other respects the feet are very primitive and 
exhibit all the unguiculate features we now invariably expect 
to find among the primitive ungulates, namely, (1) the “ cen- 
trale ” and possibly (2) the “ tibiale,” (3) the fibular facet upon 
2 
_ Fig 2. Fore and hind Feet of Meniscotherium (Hyracops) sociale after Marsh. 
the caleaneum, (4) the “astragalar foramen,” (5) the serial oF 
undisplaced facets in both tarsus and carpus. As this was the 
parent ungulate type there is no insuperable difficulty in sup- 
