60 Bulletin American Museum of Natural History: [Vol. XXXIV, 
m~. Cope misinterpreted the upper teeth, an error corrected by Wortman 
in 1892. The genus is nearly allied to Paleonictis, distinguished by the 
more shearing type of the posterior teeth. Two species are represented 
in our collection, one from the Clark Fork and lower Gray Bull levels, 
decidedly more primitive, the other from the Lysite or Lost Cabin, distinctly 
more progressive than the type species. 
The transverse m= is preserved in the more primitive species. The 
tooth may have been absent in the more progressive A. hyenoides. 
Ambloctonus priscus sp. nov. 
Type, No. 15212, fragmentary skull and jaws, etc., from the Gray Bull horizon 
three miles north of Otto in the Big Horn Basin, Wyoming. Paratypes Nos. 16116, 
16117, upper and lower jaws from Clark Fork horizon, Clark Fork Basin, Wyoming. 
Specific characters: Smaller than A. sinosus, teeth less robust, heel of ms much less 
reduced, with three cusps enclosing a basin. 
The type is a young individual with unworn teeth, and m? not yet 
erupted. No. 16116 supplies the characters of this tooth. 
Fig. 51. Ambloctonus priscus, upper teeth, type specimen, natural size, external and 
crown views. 
There are four lower premolars, much crowded, the first one-rooted, the 
others two-rooted; pz is set obliquely in the jaw. Py has two postero- 
internal cingular cusps, absent in Paleonictis, but is otherwise like that 
