MURIDA—SIGMODONTES—NEOTOMA CINEREA. 25 
Diacnosts.—NV. caudd hirsutissima, (myoxina s. subsciurina), bicolore, 
supra griseo-fusca, infra alba; corpore supra cinereo (luteo- s. badio- s. fusco- 
cinerco), infra ex albido albo. Long. tot. circ. 9 poll., caude circ. 6.00, pedis 
1.40-1.75, auricule 1. 
Haprrar.—Western and Northwestern North America. Eastward to 
Hudson’s Bay, Nebraska, and Colorado, &c. Southward to New Mexico and 
California. Westward to the Pacific. 
Since both form and color come into play in consideration of the nominal 
species we shall presently discuss, we have at once inserted our table 
of measurements, after examining which we shall note the coloration of the 
animal, and then investigate the supposed NV. occidentalis. 
In size, this animal is rather the largest of the genus, averaging near the 
maximum of floridana. The only specimen that touches 11 inches is some- 
what stretched; but as several others reach or exceed 10, 11 inches is prob- 
ably not beyond a natural maximum. Only one (No. 3898) that seems by its 
coloration to be adult falls below 7 inches, and this one appears to be some- 
what compressed in the make-up of the skin. We may safely deduce, 
therefore, striking off somewhat from both ends, an ordinary range of varia- 
tion in length from 7.50 to 10.50 inches, with an average dimension of about 
9 inches. 
The tail, as usual, is still more variable; and as, moreover, it is badly 
stuffed in most of our specimens, the true dimension is hard to reach. We 
find, as the figures stand, the vertebree running from 4.00 to 7.50 inches, and 
the hairs from 4.50 to 8.50.- Cutting off 0.50 each way for probable error, 
even then there is left a range from 4.50 to 7.00 inches for the vertebrae, and 
from 5.00 to 8.00 for the hairs. This variation amounts to nearly 33 per 
cent. of the average length of the head and body. Excluding some of the 
more striking extremes in relative length of tail to body, we may safely say 
that the shortest normal length of tail to body would be about as in No. 5662, 
or No. 1321, where the proportion is as 5: 9, or 4: 7; 56 : 100 nearly, or 
but little over half the length of the head and body; while the longest rela- 
tive length of tail is about as represented by No. 3270, where the tail is as 
70 : 85, as 82: 100, or four-fifths the head and body. But, since this 
animal (No. 3270) is supposed “occidentalis”, we might here be accused 
of assuming in the premises what we wish to find in conclusion; so we will 
take another specimen, No. 3758, from New Mexico, being typical “cinerea” 
