1913 1 Grinnell: Califomian Species of Sorex 187 



Sorex sinuosus, sp. nov. 

 Suisun Shrew 



Type. — Skin and skull, $ 3'oung adult; no. 16,470, Mus. Vert. Zool.; 



Grizzly Island, near Suisun, Solano County, California; January 5, 



1912; collected by A. M. Alexander; orig. no. 1,902. 

 Diagnostic characters. — Nearest like Sorex californicus cranially, but in 



color totally different, being blackish, with steely reflections dorsally; 



peculiar also in general size, ratio of tail to body and size of foot. 

 Coloration. — Above black mid-dorsally, with a distinct steely sheen; sides 



and lower surface, in general effect, deep clove brown; viewed closely 



there is to be seen an intermixture of bistre and grayish; fur at base 



slate-black; tail unicolor, sooty seal brown; feet (dried) hair brown; 



whiskers black. 

 Cranium. — Like that of S. californicus, nearly straight-topped in lateral 



profile, conspicuously flattened. See figure 3 and table of cranial 



measurements. 

 Measurements. — See table. 



Range. — Known only from the type locality, namely, the 

 brackish marshes of Grizzly Island, bordering Suisun Bay. See 

 list of specimens. 



Remarks. — Sorex sinuosus resembles S. californicus in shape 

 of skull, but is larger, and very much darker; californicus is 

 silver}' gray beneath, conspicuously different from the dee]) clove 

 brown of the same area in sinuosus; the former exhibits a grayish. 

 pepper-and-salt appearance above, as contrasted with the black- 

 ish hue above in sinuosus. In spite of these external differences, 

 of great degree as compared with conditions among other species 

 of shrews, the similarity in cranial outline argues the nearest 

 relationship of sinuosus to be with californicus. Sinuosus in 

 external appearance resembles halicoetes closely, but eranially 

 the latter belongs to the vagrans group of species. I am unable 

 to detect dental characters usable to my satisfaction in separating 

 any of these species. Winter skins of sinuosus are blackest, with 

 metallic sheen most conspicuous. In late summer pelage, there is 

 pronounced dulling of the sheen, apparently because of loss of 

 hair-tips. 



