SOEEOID^ 249 



Order Insectivora. (Shrews and Moles.) 

 Teeth encased in enamel; upper canine, and usually lower 

 one, present; permanent teeth rooted; lower jaw with transverse 

 condyles received in special sockets; limbs adapted for walking, 

 ulna and radius partly or wholly separated ; metacarpal bones and 

 phalanges of normal length ; toes usually five on each foot ; first 

 and second digits not opposable; feet plantigrade or subplanti- 

 grade; placenta discoidal and deciduate. 



Family Sorecidse. (Shrews.) 

 Skull long and narrow, zygomatic arches and postorbital pro- 

 cesses wanting; the two middle incisors of upper jaw large, 

 curved, with a spur-like cusp at their base; lower middle incisors 

 large and projecting forward nearly horizontally; tibia and 

 fibula united; limbs of moderate length; feet of moderate size; 

 the hind feet usually largest; nose elongated, tapering; eyes mod- 

 erately developed; external ears present; size small or very 

 small. 



This family contains about one hundred and thirty species 

 divided amOng ten genera. Individuals are most niumerous in 

 Eurasia. Shrews live in cold or temperate climates in the north- 

 ern hemisphere. They are carnivorous, much of their food be- 

 being insects, but mice and other small animals are caught and 

 eaten. Shrews are very ferocious animals, being able to conquer 

 and kill mice very much larger than themselves. They are noc- 

 turnal, principally terrestrial, occasionally semi-aquatic, rarely 

 subterranean. Seasonal chan£;es in pelage occur in many species. 



Genus Sorex Linn. (Shrew.) 



Ears small ; tail more than half as long as head and body. 



Dental formula, I, 4 — 2 ; C, i — o; P, 2 — i ; M, 3 — -3, 2'X2=32. 



The species of Sorex are difficult to determine. They are 



very small, often similar in color, with some seasonal changes of 



color. Som'e species can be distinguished with certainty only 



