Shrews 
261 
Genus SO REX (Lat., a shrew) 
Sorex Linnaeus, Syst. Nat., loth. ed., i., p. 53 (1758). Type 
Sorex araneus Linnaeus. 
Revision, Miller and Merriam, N. A. Fauna, No. 10 (1895). 
Animals of very small size; long tails; soft fur; feet without 
fringe; skull small, delicate; brain-case broad; dentition: i,|; c. ^; 
pm. f;m.| X 2 = 32; inner sides of canines and incisors without 
secondary cusps. 
The members of this genus are found in the temperate 
and subarctic portions of Europe, Asia, and North America. 
They are very small animals, frequenting meadows, marshy 
places, and woods. Their food is largely though not entirely 
insectivorous, and for their size they are extremely savage 
and voracious animals. On their bodies are glands which 
secrete a fluid having a disagreeable odor, which is a cause 
of their bodies being rejected as a food after they have been 
killed by animals or birds of prey. The young are born 
blind, naked, and toothless. 
They have two pelages called winter and summer, though 
the moults are somewhat irregular and do not correspond 
exactly with these limits. In studying and identifying the 
species it is absolutely necessary to examine the cranium 
and teeth, as the colors of some of the species are very 
similar and the differences hard to define. The most im- 
portant dental characters are the size and depth of emargi- 
nation of the molariform teeth and the proportions of the 
unicuspidate teeth. It is also quite necessary, when possible, 
to have skulls of approximately the same age for comparison, 
because of changes in the shape of the skull which take place 
with age, and in the teeth resulting from wear. The skull 
becomes broader, shorter, and flatter, the molars wear so as to 
appear broader, and the long middle incisors not only wear 
off in front but turn down at a right angle to the cranial 
axis. 
Many species and subspecies have been described in the 
