MUUID^— 8IGMODONTE8— NBOTOMA OINBREA. 



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Diagnosis. — N. caudd hirsutmhnd, {myoxina s. subsciurina), bicolorc, 

 supra f^riseo-fusca, infra olba ; corpore supra cinerco {luteo- s. badio- .«. fusco- 

 cinerco), infra ex albido albo. Long. tot. circ. 9 poll., caudce circ. 6.00, pedis 

 1.40-1.76, (luriculcB 1. 



Habitat. — Western and Nortliwcstern Nortli America. Eastward to 

 Hudson's Bay, Nebraska, and Colorado, &c. Southward to New Mexico and 

 California. Westward to the Pacific. • - ' :r ' 



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 llie supposed N. occidentalis. 



lu size, this animal is rather the largest of the genus, averaging near the 

 maximum of Jloridana. 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 ita 

 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 lO.ftO 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 vertebra; running from 4.00 to 7.50 inches, and 

 the hairs from 4.50 to 8.50. Cutting off 0.50 eacii way for probable error, 

 even then there is left a range from 4.60 to 7.00 inches for the vertebrre, 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-fif\hs 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" 



