134 Annals of the Carnegie Museum. 



M. 



Breadth of P. ^^ 005 



Greatest breadth of P. A 0065 



" " " M.i 0063 



" " " M.^. • • 0055 



" «' " M.^ 0045 



Measurements of Collateral Type (No 103). 



Depth of ramus l^elow anterior border of P.j 0105 



" " " " middle of M.j 013 



Length of inferior true molar series 0158 



" M-T 005 



" " M.T 005 



" " M 7 0058 



" P-T 007 



Greatest breadth of P.^ 005 



" M.^ 005 



" " " M.J 005 



'« " " M.J • . . . .004 



Taxonomy of Leptochq^rus. 



There has been a disposition on the part of some authorities to place 

 Leptochcerus among the Primates. This has doubtless been due to 

 the very close resemblance shown by the true molars of this genus to 

 the same teeth in certain genera of the earlier Primates, more especially 

 of the Prosimiffi or Lemurs. Most if not all of the discoveries of 

 Primates, that have from time to time been reported from the White 

 River, Oligocene formations of the West, have been based on the true 

 molars of Leptocharus. Such references of these teeth when found 

 unassociated with the premolars were very natural and quite in accord- 

 ance with our knowledge of comparative odontography. The premolars 

 are however quite unlike those of any known primate living or extinct, 

 while at the same time showing very close resemblances, as do also the 

 molars, to certain artiodactyls with the bunodont type of tooth. These 

 facts, together with certain skeletal characters referred to by Marsh in 

 his description of Z. graci/is, would appear to establish the artiodactyl 

 affinities of the genus. 



Suborder Perissodactyla. 

 Orohippus ? sp. 



In our collections of vertebrates from the White River Beds there 

 is an isolated superior molar (No. 99), which agrees in general 



