COUES ON INSECTIVOEOUS MAMMALS. 639 



sentatives of the Soricidce,or, indeed, of the order Insectivora^ are known 

 in South America. 



In North America, the differentiation of the Soricidcv into genera and 

 species has progressed farthest in the temperate and cold-temperate 

 portions of the continent. Shrews occur throughout British America 

 and the tJuited States, from AtUintic to Pacific, and north to the very 

 shores of the Arctic Ocean. These diminutive quadrupeds are endowed 

 with wonderful powers of resisting cold, generating heat enough in their 

 small bodies to endure the rigors of hyperborean winters. Their 

 rapacity, voracity, and salacity are of the highest order, and they are 

 incessantly active, never hibernating, but running freely about on the 

 snow during thes long Arctic winters. In the high north, the species are 

 few, but individuals abound, comparable in numbers with the Arvicolas 

 and Lemmings which swarm in the sphagnous regions of the Arctic zone. 

 The genus Sorex alone is known to occur in the higher latitudes, where it 

 is represented by the subgenera Sorex proper (one species being very 

 near S. vulgaris itself) and Microsorex, the latter only just now ascer- 

 tained to extend to the region of the Yukon Eiver. 



Somewhat farther south, in Northern United States and contiguous 

 portions of British Am'erica, the genera and species multiply directly. 

 Here we encounter Neosorex, and with it or directly after it Blarina, the 

 latter being the most characteristic American genus of the family. Spe- 

 cies of Neosorex are known to occur from Nova Scotia and New England 

 across to Washington Territory and Oregon, and south along the Rocky 

 Mountain chains to New Mexico. It is not yet time to map its distribu- 

 tion. I suspect that its dispersion is wider than now known. I anticipate 

 its occurrence in Alaska and other northern regions, where the present 

 evidence of its absence is wholly negative ; but I rather presume that 

 its southward extension may prove to be really limited much in the way 

 just indicated. It seems to find its centre of abundance in interior cold- 

 temperate regions, as those of the Red River of the North and the Great 

 Lakes. 



Soi'ex i)roper occurs throughout the United States; at any rate, it can- 

 not be supposed absent from any single area, so extensively is it rej)re- 

 sented by specimens now in our hands. Three or more species are pe- 

 culiar to the Pacific Province of the United States; others are generally 

 dispersed, but most abundant in individuals in northerly j)ortions of the 

 United States, where also occur the majority of the species. Exclusive 

 of the peculiar Pacific ones, all the described United States species occur 

 in New England or along the northern tier of States, this being also the 

 United States distribution of the single known species of the subgenus 

 Microsorcx {^^. hoyi), though the entire distribution of the latter must 

 not be presumed to be known as yet. 



The remarkable new subgenus Notiosorex, to be described on a suc- 

 ceeding page, is found in New Mexico and at Mazatlan, Mexico ; it is, with 

 one exception, the only representative of the genus Sorex known to occur 



