O. C. Marsh — Cretaceous Mammalia. 89 



ridge on the outer surface, but not on the inner. The pre- 

 molar, represented on the same plate, figures 20-22, apparently 

 pertains to the same species. 



These specimens indicate an animal about as large as a rat, 

 and were found in Wyoming, in the Laramie formation. 



Cinwlestes incisus, gen. et sp. nov. 



Another genus of small mammals, apparently marsupials, 

 and more distantly related to Didelphys, are well represented 

 in the Laramie by various teeth in good preservation. A 

 characteristic lower molar is shown in Plate IY, figures 12-15, 

 and this is a typical form. The anterior half of the crown 

 is much elevated, and its three cusps are distinct and sharp. 

 The posterior half is much excavated. The premolar repre- 

 sented on the same plate, figures 16-19, probably pertains 

 to the same species. They indicate an animal about as large as 

 a weasel, and are from Wyoming. 



Cimolestes curtus, sp. nov. 



A much larger species, apparently of this genus, is" repre- 

 sented by several teeth, one of which, shown on Plate IY, 

 figures 8-11, is selected as the type. It is a lower molar in 

 good preservation, and its distinctive feature are well shown in 

 the cuts. The crowns of these teeth are unusually short. The 

 remains known indicate an animal about as large as a rabbit, 

 and are from the Laramie deposits of Wyoming. 



This species and the one last described represent a distinct 

 family, which may be called the CimolestidcB. 



Pediomys elegans, gen. et sp. nov. 



Among the more minute mammalian teeth from the Laramie 

 are some that apparently pertain to a very small insectivorous 

 mammal, the exact affinities of which are uncertain. The 

 teeth secured resemble those of Tupaia. The type specimen 

 is represented in Plate IY, figures 23-25, four times natural 

 size. It is an upper molar, apparently the last on the right 

 side, and its characteristic features are well shown in the 

 cuts. Several lower teeth were found at the same locality, 

 which may pertain to this species, but their association with 

 the type specimen may be only accidental. The latter indi- 

 cates an animal about as large as a mouse, and was found in 

 the Laramie of Wyoming. 



