98 Ronald S. Caldwell and Hal Bryan 



4b. Total length usually less than 140 mm; no fringe of hairs between toes; 

 maxillary breadth less than 6.0 mm 5 



5a. Infraorbital foramen with posterior border lying behind space between 



first and second upper molars (Fig. 3A); tail longer than 50 mm 



Sorex dispar 



5b. Infraorbital foramen with posterior border lying ahead of the space 

 (Fig. 3B); tail less than 50 mm 6 



6a. Third unicuspid usually smaller than fourth (Fig. 2D); tail relatively 

 shorter, generally 32-38 percent of total length; rostrum short and 

 wide; length of posterior palate to anterior end of first incisors usually 

 less than twice the greatest width across outside of first large molari- 

 form tooth Sorex longirostris 



6b. Not with above combination of characters 7 



7a. Ventral color distinctly lighter than dorsal color; midventral hairs just 

 anterior to axillary region light from midshaft to tip; maxillary breadth 

 narrower than 4.6 mm Sorex cinereus 



7b. Ventral color not distinctly lighter than dorsal color; midventral hairs 

 just anterior to axillary region dark tipped; maxillary breadth greater 

 than 4.6 mm Sorex fumeus 



8a. Total length greater than 105 mm, or hind foot 13 mm or longer; condy- 

 lobasal length greater than 20 mm Blarina brevicauda 



8b. Total length 105 mm or less, and hind foot shorter than 13 mm; condy- 

 lobasal length less than 20 mm Blarina carolinensis 



^jj&*^ 



(B) 



Fig. 3. Infraorbital foramen position. A, Sorex dispar; B, Sorex fumeus. Ml is 

 first molar. 



