HISTORY OF THE fTOXODONTIA 



475 



the series originated in regions farther to the north, or whether 

 the ancestral types will be found in Patagonia. 



The other two families are still very incompletely known, 

 but sufficiently to justify their inclusion in the present suborder, 

 in the fLeontiniidse, which are known only from the Deseado 

 stage {]Leontinia) , we have a curious variant of the ftoxodont 

 type. The tusks were decidedly smaller than in the Santa 

 Cruz members of the preceding family, the grinding teeth with 

 lower crowns and simpler structure. The skull was much like 

 that of ^Nesodon, but the anterior nasal opening was of quite 



Fig. 241. — Skull of Adinotherium, top-view, showing the rugosity on the forehead for 

 the small frontal horn. — Princeton University Museum. 



a different shape, being carried much farther back on the sides, 

 so that the nasal bones had a far longer portion which was 

 freely projecting and unsupported ; these bones were shorter 

 and much thicker than in the Santa Cruz genera and, to all 

 appearances, supported a small, median horn on their anterior 

 ends. . The feet, so far as they have been recovered, did not 

 differ in any significant manner from those of the preceding 

 family. 



Another imperfectly known family, that of the fNotohip- 

 pidae, occurred in the Patagonian stage, but was most abun- 

 dant in the Deseado, where several genera of it have been found. 



