﻿54 



NORTH AMERICAN FAUNA. 



[No. 10. 



1890. Sorex personatus Dobscn, Mon. Insectivora, Part III, fasc. 1, PI. XXVIII, fig. 1 



(Ottawa); Pi. XXIII, fig. 10. (Manitoba.) 

 1890. Sorex richardsoni Dobsoii, Mon. Insectivora, Part III, fasc. 1, PI. XXIII, fig. 9. 



(Halifax, Nova Scotia.) 



1890. Sorex haydeni Dobson, Mon. Insectivora, Part III, fasc. 1, PI. XXIII, fig. 7, 



1891. Sorex idahoeu sis Merriam, Nortli American Fanna, No. 5, p. 32. (Idaho.) 



Tij2)e locality. — United States. 



GeograpMc distribution. — Northern North America from the Atlantic 

 to the Pacific. In the eastern part of its range Sorex lyersonatus occurs 

 m the Boreal zone, Transition zone, and locally in the northernmost part 

 of the Upper Austral zone. 



General characters. — Sorex personatus is one of the smallest Shrews 

 occurring in the eastern United States. It is slightly larger than 

 S. lonc/irostris, from which, while not differing widely in color, it is 

 readily distinguished by its slender muzzle as well as by dental char- 

 acters. 



Color. — Dorsal surftice of body sepia tinged with chestnut on rump, 

 lumbar region, and sides of head, fading on the sides of the body; 

 belly, throat, and chin silvery smoke gray or pale broccoli ])rown; no 

 sharp line of demarcation between color of belly and sides, but change 

 taking place rather abruptly. Throughout the pelage the hairs are 

 slate color at base. On the back, especially just behind the shoulders, 

 the fur IS usually a little intermixed with grayish. Tail obscurely 

 bicolor, brownish dorsally, paler ventrally. Dorsum of manus and pes 

 Isabella color. 



SlinlL—The skull of Sorex personatus (PI. YI, figs. 7, 8) is scarcely 

 distinguishable from that of the European Sorex minutus (PI. VI, fig. 6). 

 As in the latter, the brain case is moderately high and rounded and 

 the rostrum slender. The palatal depth at middle of molar series is 

 less as compared with the cranial depth in all the members of the 

 minutus group than in those of the araneus group. This is readily 

 seen in comparison of the skulls of S. personatus and S. richardsoni 

 (see table, page 43). 



Teeth. — The teeth of Sorex personatus very closely resemble those of 

 S. minutus^ the only differences being in the relative size of the first 

 premolar and in the form of the excavations on the posterior borders 

 of the upx^er molariform teeth. The first premolar in S. personatus is 

 minute and often scarcely visible from the outer side, while in S. minu- 

 tus it is nearly as large as the canine. The deepest part of the exca- 

 vations on the posterior borders of the upper molariform teeth is near 

 the middle of the tooth in >S^. minutus^ w^hile in S. personatus it is car- 

 ried farther toward the inner edge. The unworn unicuspid teeth of 

 S. personatus (PI. lY, figs. 1, 5, 6, and 7) vary considerably in form, pig- 

 mentation and relative size. The first, second, third, and fourth, how- 

 ever, diminish graduall}^ in size, while the fifth is very small. The third 

 incisor is usually slightly larger than the second, and distinctly larger 

 than either the fourth incisor or the canine. The fourth incisor and the 



