28 Bulletin American Museum of Natural History. [Vol. XXXIV, 
Distinctive characters: Premolars high, short, compressed, like those of Miacine. 
A small posterior accessory cusp on ps4, none on ps3. 
NolS5181 ir 
A. / le | \ M12 7.5 mm. 
This species is smaller than V. dawkinsianus 
and readily distinguished by the proportions of the 
premolars, very different from the elongate teeth of 
all other Viverravine and resembling those of Miacis. 
; The molar teeth are reduced copies of dawkinsianus. 
Fig: 22, Viverravus ; : s a 
acutus, upper jaw frag- live lower jaws Nos. 15174, 15181, from the Gray 
ment with molar teeth, Bull beds and Nos. 89, 90 and 4247 from the Big 
enlarged to two diam- ‘ ; 
eters, and outline of nat- Horn basin, probably Gray Bull beds, are referable 
ural Size. No. 15181, to this species but all somewhat more progressive 
Gray Bull beds, Big Horn ‘ + ; _ 7 
Basin. in the direction of V. dawkinsianus. 
Viverravus politus sp. nov. 
Type, No. 16113, lower jaws with my_sr, psx-mzl., from Sand Coulée beds in Clark 
Fork Basin, Wyoming. 
Distinctive characters: Premolars short and high, as in Miacis; my». = 12.5 mm. 
This species, like V. acutus, retains the short high premolars of Miacis, 
but is a much larger animal, intermediate in 
size between V. gracilis and V. sicarius. cy 
No. 15180, comprising parts of both rami 
of the lower jaw from the Gray Bull Beds, Big 
Horn Basin, is referred to this species but is 
somewhat larger and more robust than the 
type. 
Viverravus dawkinsianus (Cope 1881). 
Didymictis dawkinsianus Corr, 1881, Bull. U.S. 
Ce Tere, Volk Vi, p..191: 1885, Tertiary Verte- . te ee 
brata, p. 310, pl. xxva, fig. 11; (Viverravus) Wort- P | 
MAN, 1899, Bull. A. M. N. H., Vol. XII, p. 136. et 
Type, No. 4788, lower jaw from the Lost Cabin Sn 
horizon of the Wind River Basin, Wyoming. Fig. 23. Viverravus politus 
Distinctive characters: Premolars long, com- lower teeth inner and outer 
pressed, not high, prominent posterior accessory Views enlarged to two diameters, 
cusps on pz and py. Length of p,_4 less than twice tly eats aprile inci 
M1-2; Pr-Mz (approximately) = 27.5; mi, = 10mm. Oneida take, Clark BP fyi. 
This species is closely allied to V. gracilis. I can find no evidence for 
Cope Ss statement that p; has but one root, but the premolar portion of the 
