482 LAND MAMMALS IN THE WESTERN HEMISPHERE 



and two transverse crests, as in the fToxodonta, and the lower 

 molars were composed of two incomplete crescents. The 

 teeth were present in undiminished number and the anterior 

 incisors were but little enlarged. Nothing is known of the 

 skeleton. 



Suborder fENTELONYCHIA. fHOMALODOTHERES 



This third suborder of the tToxodontia was in some respects 

 the most peculiar of all ; no representatives of it have been 

 found in formations later than the Santa Cruz, and the group 

 attained its culmination in the still older Deseado stage, in 

 which there were very large members of it. These most extraor- 

 dinary beasts are still incompletely known, and httle can be 

 done as yet in the way of following out the steps of change 

 which led up to their exceptional characters, though the sub- 

 order itself may be traced back to the Eocene by means of 

 jaws and teeth alone. 



The Santa Cruz genus labours under the portentous name of 

 ^Homalodontotherium, which may be shortened to the ver- 

 nacular form of fhomalodothere. In this genus the dentition 

 was unreduced in number, and the teeth, though having rather 

 high crowns, were all rooted and placed in continuous series, 

 with a gradual transition in shape from the incisors to the 

 molars. The canines were tusks of very moderate size, which 

 projected but little above and below the plane of the other 

 teeth ; the premolars, except the last, which was nearly mo- 

 lariform, were smaller and simpler than the molars, which had 

 a pattern fundamentally the same as in the fToxodonta. 

 Those of the upper jaw were, however, less complicated by 

 spurs and accessory crests, and they had a somewhat stronger 

 resemblance to the rhinoceros pattern, though the resemblance 

 is demonstrably superficial and not indicative of relationship. 



The skull was very like that of the Santa Cruz ftoxodonts, 

 ^Nesodon, etc., and had the same unusual structure of the audi- 

 tory region as was found throughout the order, but differed in 



