141 
Specific Characters.—As this is the only representative of its genus, and 
as the above enumeration of generic characters is unusually full and 
minute, it is only necessary to mention a few other characters which are 
taken from Dr. Coues’s Monograph above cited. 
The length, from nose to end of tail vertebre, is from 74 to 104 inches, 
averaging about 8 inches. The body and tail are usually about equal. 
The color is mixed yellowish and grayish-brown, and black; darker 
along the back, shading on the rump and sides into the whitish of the 
under parts. The hands and feet are densely or scantily covered with 
satiny, whitish, appressed hairs. The palms and soles are flesh-colored 
or blackish. The palms are 5, the soles 6 tuberculate. The third finger 
is longest, the fourth a little shorter, and the second and fifth diminish 
rapidly. The second, third, and fourth toes are very long and nearly 
equal; the fifth reaches nearly to the middle of the fourth, the first 
scarcely beyond the base of the second. The claws are short, thick, little 
curved, not very sharp. The size of the foot is in striking contrast with 
the shortness of the leg. 
The habitat of this species is the south Atlantic and Gulf States, es- 
pecially in maratime portions, and in rice fields. It has also been 
reported from Kansas and Mexico. 
This large, rat-like species is the type and only representative of the 
sub-genus Oryzomys. It is eminently aquatic, only surpassed in this 
respect by the Muskrat. 
It has been identified by Mr. Frank W. Langdon, ‘‘ with some hesita- 
tion, on the strength of the posterior half of a small Rat found in the 
stomach of a Red-shouldered Hawk, killed December 24, 1876,” at Mad- 
isonville, Ohio. The writer has since examined Mr. Langdon’s specimen, 
and finds that the feet and tail agree, in the minutest details, with the 
very full description given by Dr. Coucs, in the Monographs of North 
American Rodentia. 
—FHesperomys (Vesperimus) aureolus (Aud. & Bach.) Wagner, the Red 
Mouse, inhabits the central and southern States (Coues), but there is no 
record of its residence in Ohio known to the present writer. 
GENus ArRvicota Lacépéde. 
This genus, as defined by Dr. Coues, is equivalent to the sub-family 
Arvicoline, excluding the Lemmings, the Synaptomys, of Baird, and the 
rooted-molar group, Evotomys. 
Generic Characters—Molars $23, rootless, perennial, and prismatic ; 
crowns of molars divided into several closed islands of dentine by folds 
