



nsro. 3. 



THIRD ACCOUNT OF NEW VERTEBRATA FROM THE BRIDGER 

 EOCENE OF WYOMING VALLEY. 



By Edward D. Cope. 

 Stypolopus insectivortjs. Cope. Sp. nov. 

 Represented by a posterior molar and a premolar of the right side of 

 an animal less than half the size of the 8. pungeus, Cope. The molar 

 presents three anterior trihedral acute tubercles, of which one is exterior 

 and more elevated than the others. Its posterior plane forms one trans- 

 verse face with that of the inner posterior. The posterior tubercular 

 heel is low, and supports an oblique ridge which bounds a deep groove 

 behind the outer cusp, no doubt to receive that of the upper jaw. This 

 arrangement is not seen in 8. pungeus. The premolar is a flat cone with 

 faint traces of a tubercle behind and cingulum on inner side. 



M 



Length crown molar 0.0050 



Height inner cusp 0040 



Length heel 0025 



Width crown 0030 



Height crown premolar 0040 



Length " " -0040 



Found in the Eocene Bad Lands of Black's Fork, by tbe writer. 



Stypolophtjs BREVicot,CARABrjs. Cope. Sp. nov. 

 Established on a portion of the left mandibular ramus, containing the 

 penultimate and ante-penultimate molars, of an animal of a larger size 

 than the type of the genus 8. pungeus. The molars have the general 

 characters of the corresponding ones of that species, but differ in tbeir 

 greater elevation in comparison with their length, and the greater convexity 

 of the outer side. The shortness is occasioned by the abbreviation of the 

 heel, which in the last molar present, is very small and flat, without keel 

 or tubercle on its surface. That of the molar preceding it is larger, 

 and presents in its elevated outer margin, a trace of the keel seen in the 

 smallest species. Enamel smooth. 



M. 



Length of two molars 0.016 



" " penultimate crown 008 



Width " " " 0047 



Length" " " 002 



There is some relation between Stypolophus and Triacodon, Marsh. If 

 the heel of the molars of the former were wanting, they would be those 

 of the latter. The premolars might be supposed to have this structure, 

 but the form seen in 8. insectivorus disproves this view. In fact, I have 

 seen both molars and premolars of Triacodon aculeatus, Cope, and the 

 former lack the heel of the 8typolop7ii entirely. 



