^tf, 



nsro. 2. 



SECOND ACCOUNT OF THE NEW VERTEBRATA FROM THE 



BR1DGER EOCENE. 



By Edward D. Cope. 



Helotherium procyoninum. Cope. 



Spec. nov. 



This species is distinguished from those already known as pertaining 



to this genus, by its small size, as it does not much exceed the raccoon in 



dimensions. The size of a right superior molar is as follows : 



M. 



Length 0.007 



Width posterior 0085 



" anterior 006 



The crown presents four tubercles, of which the inner are flat on the 

 posterior, the outer flat on the external side. The posterior external has 

 a small posterior supplementary lobe, and a low tubercle intervenes be- 

 tween the two posterior. An anterior and a posterior cingulum. Enamel 

 smooth. 



Stypolophus punoens. Cope. 

 Gen. et spec. nov. 

 This genus is supposed to embrace a small species of carnivorous ani- 

 mal found by the writer in the Eocene formation of the Bridger Group, 

 It is represented by the posterior portion of the left mandibular ramus, 

 which contains the last two molars. 



The generic characters are seen in the composition of these molars, 

 which have but two roots, and a posterior table, as is seen in tubercular 

 molars of some mustelidce. The anterior, two-thirds of the crown is com- 

 posed of conic cusps. On the last molars these are in two series, two 

 lower of the inner, and one more elevated, of the outer, opposite the in- 

 terval between the outer. Its Outer face is regularly convex, but its 

 posterior forms, with that of the outer series, a single flat vertical plane, 

 which forms a sharp angle with the inner and outer faces of the cusps. 



The structure is, in general, somewhat like that of Mesonyx, Cobe but 

 the lack of cutting edge on the posterior lobe, and the two rows of tuber- 

 cles separates it at once. Dr. Leidy describes Sinopa, as having a sec- 

 torial tooth as in ordinary Carnivora, with an interior cusp, hence it is 

 not probably the present form, although this species was about the size 

 of the S. rapcex. 



The enamel is smooth. The measurements ax*e : 



M. 



Depth ramus at last molar 0.011 



Length last molar 0072 



Width " posteriorly 0040 



Height inner tubercle 0062 



" external " 0040 



This species was about the size of the gray fox. 

 From the bluffs of Cottonwood Creek, Wyoming. 



