MURIDZ—ARVICOLINA—ARVICOLA CURTATUS. 215 
ARVICOLA (PEDOMYS) AUSTERUS CURTATUS, (Cope.) 
Western Prairie Mouse. 
Arvicola curtata, Corr, Proc. Acad. Nat. Sci. Phila. Jan. 1868, 2 (“Pigeon Springs”, east of Owen’s Valley, 
California), (type examined). 
Arvicola pauperrima, Coor.?, Am. Nat. Dec. 1868, 535 (Great Plains of the Columbia), (type examined). 
Arvicola (Pedomys) austerus var. curtatus, CouES, Proc. Phil. Acad. 1874, 190. 
Cuars—Tail obviously shorter than head. Brownish-gray, beneath 
much paler, sometimes nearly white. Size of austerus, or rather less. Four 
inches or less; tail vertebree an inch or less; hind foot # of an inch or less. 
Hasiratr.—United States, west of the Mississippi. California (Gadd, 
the type; Feidner). Great Plains, Washington Territory (Cooper). Colorado, 
Kansas, and Nebraska (Hayden, Goss), where mixed up with austerus. 
In handling the present Smithsonian series to pick out our western 
styles of A. riparius, we here and there happened upon a specimen looking 
quite different from any of the many western strains of riparius, and these 
we put aside together for final determination. They were smallish, with 
extremely short tail, light gray above and correspondingly pale below, and, 
though they differed inter se to a puzzling degree, we could not believe them 
referable to any variety of riparius. None, unfortunately, were accompanied 
by separately cleaned skulls; but on wrenching open the mouths of the 
specimens, as we were obliged to do in every instance, we found, to our 
surprise, that they were all typical Pedomys in dentition, and so entirely 
different from any breed of Arvicola riparius. The westernmost of them 
were at the same time very different from the blackish muddy-bellied and 
comparatively long-tailed Illinois austerus, yet Kansas specimens were com- 
pletely intermediate, through the paler-style of austerus called haydent by 
Baird. Up to this time we had not thought of Arvicola curtatus Cope. That 
species being compared with “ modesta” by its author, and not being indi- 
cated as a Pedomys at all, we had concluded that it was probably another of 
the everlasting kinds of riparius. Desiring, however, more positive evidence, 
we wrote to Professor Cope requesting a view of his type, which was 
promptly sent to us, when we were gratified to perceive, as we did at a 
glance, that our animal, to which, curiously enough, we had applied in man- 
uscript nearly the same name (‘‘decurtatus”) was Cope’s species. 
Owing to bad taxidermy and neglect to poison the skin, the type of 
curtatus was almost entirely destroyed. As it reached our hands, nothing 
