Genus Reithrodontomys 121 
County, June 26th) : Above rather pale vinaceous buff, rather Hghtly 
Hned with black on dorsal region; feet and under parts white; 
tail less bushy than orolestes and arizoncB, blackish above, white 
below. As compared with N. arizoncB it is a much paler animal 
of a very different shade of color, the latter being almost rufous 
in comparison, and with much more black. 
Distribution. — The Cinnamon Wood-rat is found in southwestern 
Wyoming and in northwestern Colorado. In the latter State it has 
only been found in the Escalante Hills, in western Routt County, 
where it was taken by myself in 1907. 
Habits. — Nothing special is known about the habits of this 
species. I found it in the rocks. Well grown young were 
taken in late June. 
Subfamily CRICETIN^E 
Rodents of rather varying external form in which the 
molars are tuberculate and rooted; those of the upper jaw 
having the tubercles arranged in a double longitudinal row 
instead of in a triple row as in the MurincE: skull rather 
short and broad with a rather short rostrum and with the bony 
palate ending about opposite the end of the molars. 
A large subfamxily of cosmopolitan distribution and of 
somewhat generalized structure from which it seems probable 
the more specialized MurincB have been evolved. 
Genus REITHRODONTOMYS (Grk. reithron, a channel, + 
odous, tooth, + mus, mouse, channel or groove -toothed 
mouse). 
Reithrodontomys GigHoli, Richer. Dist. Geogr. Gen., Roma, p. 60 
(1873). Type R. lecontei. 
Revision, Allen, Bull. Amer.Mus. Nat. Hist., vii., p. 125 (1895). 
Small, slender, mouse-like rodents with the tail about as long 
as the body without the head ; skull with the anteorbital foramen 
situated in the zygomatic portion of the maxillary, almost circular 
above, contracting to a slit below; dentition, i.|;m.f X 2 = 16; 
upper incisors with a deep longitudinal groove in front, which 
at once distinguishes this genus from Peromyscus, the only genus in 
Colorado likely to be confused with it; lower incisors simple; 
anterior upper molars with four roots, three large, one small. 
