560 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Measurements. 



M. 



Depth ramus at last molar 0. Oil 



Len^jtli last molar 0U7'2 



Widt Ii last molar, i)osteriorly •. 0040 



Heigbt inner tuberclo OOOi 



Height external tubercle, (anterior) 0040 



This species was about tlic size of the gray fox. 

 From the bluft's of Cottonwood Creek, Wyomiug. 



« 



STYPOLornus beevicalcaeatus, Cope. 



Log. oit., p. 469; published August 7, 1872. 



EstablisliecT on a portion of tlie left mandibular ramus, containing the 

 I)enultimate and ante-penultimate mohirs, of an animal of larger size 

 than the type of the genus, /S\ imngens. The molars have the general 

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

 greater elevation in comparison with their length, and the greater con- 

 vexity of the outer side. The shortness is occasioned by the abbrevia- 

 tion of the heel, which, in the last molar present, is very small and flat, 

 without keel or tubercle on its surfece. 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. 



Measurements. 



M. 



Length of two molars 0.016 



Leugth.of penultimate crown 008 



Width of penultimate crown 0047 



Length of penultimate heel 002 



There is some similarity between ^iDpoJopltus and Trlacodon, 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 S. hiscctivoms disproves this view. 

 In fact, I have seen both molars and premohirs of Triacodon aculeatiis, 

 Cope, and the former lack the heel of the iStiipoJophi entirely. 



YIVEEEAYUS, Marsh. 



Amer. Journ. Sci. Arts, 1872, p. 127. 



VlVERRAVUS PARVIYORUS, Copo. 



Miacis jyarvivorns, Cope. Proceed. Amer. Philos. Soc. 1872, p. 470, August 7. 



Established on a portion of the right ramus mnndibuli, containing 

 portions of three molars, the penultimate being perfect. As in Caniikc^ 

 the molars diminish in size jiosteriorly, the last being single-rooted, the 

 penultimate being two-rooted. The structure of that tooth is approxi- 

 mately that of Stypohjjhns, i. e., with three trihedral cusps in front and 

 a heel behind ; but the cusps are of equal height, and their point of 

 union not raised above the surface of the heel. This is a valley bounded 

 by a sharp margin which is incurved to the outer cusp, leaving a ver- 

 tical groove on the outer side, as in Stiqwlophtis sj). This genus further 

 differs from that one in the single-rooted, small, tubercular posterior 

 molar, which is wanting in that one. The ante-penultimate molar is 

 much larger than the penultimate. The crown of th(> latter is laterally 

 expanded, and bears a cingulum at the base anteroexterually. Enamel 

 smooth. 



