INSECTIVORA : SORICID^E. 2/ 



SORICID/E, OR SHREW FAMILY. This Family is charac- 

 terized by a general mouse or rat-like appearance, elon- 

 gated and tapering muzzle, ears with distinct concha, and 

 fore feet smaller than the hind ones. On either flank, 

 or at the base of the tail, are situated peculiar glands 

 which emit an unpleasant odor. In true Shrews the teeth 

 vary from twenty-eight to thirty-two in number. The 

 dental formula is generally regarded as, incisors ^ 

 premolars - - to , molars . The two large incisors 



2-2 2-2' 3~3 



in each jaw are directed nearly horizontally forwards, 

 the upper pair curved into a hook, and the lower are 

 straighter, and with the trenchant upper edge more or 

 less lobed. Shrews are found all over the world, and 

 more than twenty species belonging to North Amer- 

 ica, and distributed among three genera, have been de- 

 scribed. They live under rubbish, and in burrows which 

 they dig in the earth. 



The Genus Ncosorex is characterized by rather short, 

 valvular ears, partly furred on both surfaces. 



The Water Shrew, N. navigator, 

 Cooper, found at Fort Vancouver, 

 is two and one twelfth inches long 

 to the tail, which is three inches ; 

 the color dark sooty-brown above, water shrew, 



grayish-white beneath. N - navigator, Cooper. 



The Genus Sorex is characterized by large valvular 

 ears, concha directed backwards, tail about as long as 

 the body without the head, feet of moderate size and not 

 fringed, the upper forward incisor with a second basal 

 hook, and a small angular process on the inner side near 

 the point. 



Trowbridge's Shrew, 6". Trowbridgii, Baird, of West- 

 ern North America, is two and a half inches long to the 

 tail, which is two inches ; the color sooty-brown above, 

 paler beneath. 



