﻿Dec, 1895.1 



SOREX PERSONATUS. 



61 



Cranial and dental characters. — Skull small, rather slender; i^alate 

 narrow and arched ; anterior part of rostrum compressed and attenu- 

 ate; unicuspids decreasing- in size from first to fifth. (Viewed from the 

 side they are sometimes in pairs, first and second subequal and third 

 and fourth subequal.) Specimens from the northern i^lains have the 

 anterior part of the rostrum slightly more attenuate, with the unicus- 

 pidate series nearer together and more nearly parallel. The unicuspid 

 teeth also are more crowded, more vertical, less imbricating, and some- 

 what more heavily pigmented. This form Tvas u^med for steri by Rich- 

 ardson, but the characters are inconstant and are matched by some 

 specimens from the east, notably from Montauk Point, Long Island, 

 New York. 



Measurements. — Average of 8 specimens from Montauk Point, Long 

 Island, New York: Total length, 98.3 mm. ; tail vertebrie, 38 mm.; hind 

 foot, 12 mm. Average of 4 from Roan Mountain, North Carolina : Total 

 length, 100.5 mm.; tail vertebrae, 41 m'm.; hind foot, 12.3 mm. (For 

 table of measurements see p. 63.) 



General remarks. — Sorex personatus, the common Shrew of the east- 

 ern United States, has a larger area of distribution than any other 

 American species, stretching all the way across the continent from New 

 England to Alaska. Throughout this wide range its variations are 

 surprisingly slight. Certain inconstant departures have been already 

 mentioned under the skull characters. In coloration also there are 

 geographic differences. The most marked of these is a pale form from 

 the prairies and plains of the Dakotas. In this animal the whitish of 

 the under parts reaches far up over the sides, and is bordered above by 

 a baud of bufiy, restricting the dark color of the back to a dorsal 

 band. This tricolor pattern is well shown in a specimeu from Port- 

 land, N. Dak. (No. 3G851, U. S. Nat. Mus.), collected October 26, 1892, by 

 J. Alden Loring. This form was separated by Band, under the name 

 S. haydeni, and is probably entitled to recognition. Another form that 

 will probably require separation comes from the extreme southern limit 

 of range of the species, where it overlaps from the Transition into the 

 Upper Austral or Carolinian zone. If worthy of recognition, it will 

 probably take the name lesueuri, proposed by Duvernoy in 1842 for a 

 specimen from Wabash Valley, Indiana. Specimens of this form are 

 extremely rare, and have been examined from only two localities — 

 Sandy Spring, Md., and New Harmony, Ind.' 



Specimens of S.personatus from the Rocky Mountains, near the east- 

 ern boundary of British Columbia (Field and Glacier), are noticeably 

 larger and have larger skulls than those from the neighboring plains 

 on the east, in which respect they tend toward subspecies streatori of 

 southeastern Alaska. 



1 Unfortunately, the skull of the specimen from New Harmony can not be found. 



