476 Bulletin American Museum of Natural History. [Vol. XXXIV, 
intermediate between C. latidens and C’.. angustidens (infra). No. 15629, a 
weil preserved upper jaw from the Bighorn Lysite affords satisfactory 
distinctions from the upper jaws of C. scotttanus and Microsyops. 
Osborn has referred Pelycodus angulatus of Cope to this genus. The 
specimen figured by Cope in 1885 appears to be specifically the same as C. 
latedens. 'The original type specimen, from the Wasatch of New Mexico, 
is lost, but Cope’s figure and description of it do not accord well with this 
species, and it does not appear advisable to synonymize it. Two small 
species from the Wind River Lysite horizon described by Loomis in 1906 as 
Notharctus palmeri and cingulatus appear to me to be based, upon the teeth 
of Cynodontomys, probably C. latidens. 
The species is distinguished’ from C. scotttanus by somewhat smaller 
size and narrower teeth, p# less molariform. The inner cusp (de") of ps is 
less distinct and lower, the posterior outer cusp (trittocone) of p* is smaller 
— 
wih 
\ 
~~ 
‘i 
= 
WAP eO 23 
A. /1.« Vg 
3 ff 
MZ 
Fig. 47. Cynodontomys angustidens, lower jaw, inner, outer and crown views, enlarged 
three diameter. Outline of jaw, natural size. Type specimen, Gray Bull beds Bighorn 
basin, Wyoming. . 
