1378 



CLASS MAMMALIA. 



therium {Mes other iuni) from the infra-Pampean beds of Argentina, 



i o 23 



in which the dentition is I. -', C. — , Pm. -, M. ~. The incisors 



2 o' 1' 3 



grow from persistent pulps ; and the structure of the cheek-teeth 

 recalls that of Toxodon. The skull (fig. 1252) is of an Ungu- 

 late type ; there is a third trochanter to the femur • and clavicles 



Fig. 1252. — Skull of Typotlierium cristatum ; from the infra-Pampean of Argentina. 

 One-half natural size. 



(which are unknown in any other Ungulate) are present. This 

 peculiar genus presents characters connecting the Toxodontidce with 

 the Rodents. Allied forms from the infra-Pampean deposits of the 

 same region have been described as Protyflotherium, Stenotephanus, 

 and Tonwdus ; while Pachyrucus from the later Tertiary of Monte 

 Hermosa is a much smaller form with three premolars. 



Suborder 4. Condylarthra. — This group comprises a number 

 of very generalised Ungulates mostly from the Eocene of North 

 America, which are grouped by Professor Cope, on account of the 

 structure of their feet, with the Hyracoidea in a division termed 

 Taxeopoda. 1 Both the present group and the Hyracoidea are 

 characterised by the scaphoid of the carpus being supported by the 

 trapezoid and not by the magnum, which carries the lunar ; while 

 in the tarsus the cuboid articulates proximally with the calcaneum 



1 Professor Cope would also include the Primates among the Taxeopoda. 



