624 INSECTIVORA 



some writers as Microsorex), of the same country, this tooth is 

 rudimentary. 



Other North American Shrews, which are regarded by some 

 zoologists as generically distinct under the name of Neosorex, are 

 aquatic, and thus take the place of the Old World genus Crossopus. 

 These are S. palustris of the Rocky Mountains and S. hydrodromus of 

 Unalaska Island, both of which resemble Crossopus in having the 

 feet provided with swimming fringes, but agree with the other 

 species of Sorex in their dentition and the character of the tail. 

 The former species is about the size of Crossopus fodiens, while the 

 latter is scarcely larger than S. pygmceus. 



Soriculus. 1 Dentition : i 4, c , p -j , m f ; total 30, or rarely 

 32. Opening of male or female generative organs forming with the 

 anal orifice a shallow cloaca. Ear and tail as in Sorex. First upper 

 incisor with an internal cusp. Habits terrestrial. 



This genus is the only representative in the Oriental region of 

 the Soricince, which are otherwise confined to the Palsearctic and 

 Nearctic regions. The Indian and Burmese species comprise 

 S. nigrescens, S. cauctftfus, and S. macrurus. 



Notiosorex? Dentition : i f , c , p ^, m f ; total 28. Tail 

 moderate ; first upper incisor without an inner cusp ; other 

 characters as in S&riculus. Habits terrestrial. 



This American genus is represented by S. crawfordi and S. evotis, 

 which are found in Central America and Mexico, and are thus some 

 of the most southerly representatives of the Shrews in that con- 

 tinent. Their external appearance is very similar to that of the 

 Old World genus Crocidura. 



Marina. 3 Dentition : i --~- , c , p -f- , m f ; total 32 or 30. Ear 

 truncated above ; tail short ; otherwise as in Soriculus. This group of 

 so-called Earless or Short-tailed Shrews is mainly North American, the 

 common forms being B. dekayi and B. brevicauda. The species vary 

 considerably in size ; and B. mexicana and micrura extend the 

 range of the genus into Mexico and Guatemala. The following 

 account of the habits of B. brevicaudd is taken from Dr. Merriam's 

 Mammals of the Adirondack Region : " The rigours of our northern 

 winters seem to have no effect in diminishing its activity, for 

 it scampers about on the snow during the severest weather, 

 and I have known it to be out when the thermometer indi- 

 cated a temperature of - 20 Fahr. It makes long journeys 

 over the snow, burrowing down whenever it comes to an 

 elevation that denotes the presence of a log or stump, and I am 

 inclined to believe that at this season it must feed largely upon 



1 Blyth, Journ. As. Soc. Bengal, vol. xxiv. p. 36 (1855). 2 Coues, Bull. 



U.S. Geol. Surv. Terrs, vol. iii. p. 646 (1877). 3 Gray, Proc. Zool. Soc. 



1837, p. 124. 



