﻿Deo, 1805.] 



GENUS NOTIOSOREX. 



31 



BLARINA NIGRESCENS Allen. 



Blarina (Soriciscus) nigrescens Allen, Bull. Am. Mus. Nat. Hist., New York, VII, p. 339, 

 November 8, 1895. 



Type locality. — iSau Isidro (San Jose), Costa Eica. 



''Pelage coarse, rather long, and not lustrous. Above dusky plum- 

 beous, in some lights black; lower surface not appreciably diiferent. 

 Feet and tail blackish, nearly naked, the annulations of the latter being 

 distinctly visible. 



''Measurements. — Head and body, 65 mm.; tail vertebrae, 22 mm.; 

 hind foot, 12 mm. 



" SlaiU. — Total length, 20 mm.; mastoid breadth, 9.5 mm.; length of 

 nasals, 7 mm.; length of upper tooth row, 9 mm.; distance between 

 outer edges of last molars, 6.3 mm." 



General remarks. — Blarina nigrescens is closely related to B. nelsoni, 

 from which it may be distiuguished by the even larger size of the large 

 upper i^remolar. This tooth is exceedingly broad transversely and is 

 strongly convex on its inner side. Its anterior cusp is nearly obsolete, 

 while in nelsoni it is well developed. As in nelsoni, all the molariform 

 teeth are very large and very slightly excavated posteriorly. The uni- 

 cuspidate teeth have the inner cusplet fairly developed; in nelsoni it is 

 nearly obsolete. The skull is slightly smaller, and the brain case 

 narrower behind than in nelsoni. 



Genus NOTIOSOREX Baird, 1877. 



Notiosorex (subgenus of Sorex) Baird in Coues, Bull. U. S. Geol. and Geog. Surv., 

 Ill, 1877, 646-647. 



Notiosorex (full genus) Dobson, Mon. Insectivora, Part III, 1890, PI. XXIII, fig. 20. 



Flower and Lj'dekker, Introduction to Study of Mammals, 1891, 624. 

 Merriam, Proc. Biol. Soc. Washington, YII, 1892, 26. 



3 1 13 8 16 



Dental formula. — i, ^'^ pm, j; m, ^ = ^ x 2 = ^ = 28. 



Teeth; 28; unicuspids, 3, forming a uniform series, the third more 

 than half as large as second, never minute. Unicuspids narrow at 

 base, without trace of secondary cusplet on inner side. Anterior teeth 

 lightly tipped with orange; molars pure white. Cranium flat and 

 broadly rounded. External ear conspicuous; 

 tail short, less than half the length of head 

 and body ; body slender. 



Geograpliic distribution. — Lower Souoran 

 fauna of the United States and Mexico, from 

 southern Texas to southern California and southward in Mexico to 

 Mazatlau, Sinaloa and the peninsula of Lower California. 



Fig. 2.— Skull of Notiosorex. 



