MAMMALS—SORICINAE—SOREX TROWBRIDGII. 13 
SOREX, Linn. 
Ears large, valvular, concha directed backwards, pattly furred on both surfaces ; tail about as long as the body, (exclusive 
of the head,) or longer, its hairs of equal length, except at the tip; feet moderate, not fringed ; skull slender anteriorly 
and elongated; upper anterior incisor with a second basal hook, and a small angular process on the inner side, near the 
point ; two anterior lateral teeth somewhat larger than the next. 
The genus Sorex is common to both the old world and the new, and embraces a large pro” 
portion of the known species. The former have all five premolars, as in most of the American, 
and belong to the subgenus Corsira of Gray. I see no reason, however, for using either this 
name or Amphisorex of Duvernoy, in preference to Sorex, as the genus was established by Lin- 
nacus in 1754, upon the species S. vulgaris, belonging strictly to the present group,! and very 
similar in dentition to Sorex forstert. 
The genus is divisible into two sections, one with 32 teeth, the other witli 30; this difference 
accompanied by others hereafter to be mentioned. Most of the species belong to the greup with 
32 teeth. For the subdivisions of these sections see the list of species at the end of the article 
on the Sub-family Soricinae, page 10. 
To the first group of the table, or those in which the third premolar is smaller than the fourth, 
belong all the species west of the Rocky mountains. The second group, with the gradation 
‘gradual, and the teeth imbricated, includes also the European members of the genus. This and 
the third division belong to the eastern and central portions of the continent. The species with 
30 teeth have not been found south of the parallel of northern Ohio. 
Section A, WITH FIVE UPPER PREMOLARS, TEETH 32. 
Ears distinct, though not projecting visibly beyond the hair, furred on both sides; snout 
attenuated ; tail as long as the body, (exclusive of the head,) or longer, light colored beneath ; 
dental formula : +- = —- = = 32; anterior ‘upper incisor with a well developed basal 
hooked process and an internal lobe, usually in contact with its opposite; fifth lateral tooth 
very small ; lower anterior incisor not extending backwards to the first molar, cutting edge with 
two or three lobed dentations ; the first lateral tooth and half the second inserted above the base 
of the anterior incisor; teeth white, light chesnut only on the points; skull slender; feet 
moderate, not fringed ; colors generally lighter beneath ; no colored points on the inside of the 
lateral upper teeth at the base ; lower angular process of lower jaw long and slender. 
1. Third upper premolar smaller than the fourth. 
SOREX TROWBRIDGII, Baird. 
Sp. Cu.—Ears very large, not exceeding the long fur ; fur full, longest hairs measuring over three lines; fore feet broad, 
contained 1} times in the hinder, which are barely a little more than two-thirds the length of the skull; tail as long as the 
body and half of the head ; third lateral incisor smaller than the fourth; anterior upper incisor with a moderal internal lobe. 
Color above, sooty brown or black, slightly variegated with hoary; beneath, a little paler, and very slightly different 
from the back ; head and body, 2} inches; tail, 2 ; hind feet, over five-tenths of an inch. 
Body slender, elongated ; snout rather broad, depressed, and pointed; whiskers numerous, 
moderately long, and light colored ; eara unusually large, although not longer than the fur on 
1 See Nathusius in Wiegmann’s Archiv, 1838, 45. 
