632 



REPORT OF STATE GEOLOGIST. 



Vespertilio fuscus Miller, N. Am. Fauna, No. 13, p. 96, 1897. 



Eptesicus fuscus Miller, Bull. 57, U. S. Nat. Mus., p. 208, 1907. 



Diagnostic characters. — Size large (four inches or more). Color 

 bright glossy brown ; skull very broad, massive and low. 



Description.— The color of the back is always a rich glossy 

 brown, although the shade varies considerably. The underside is 

 paler, the belly being sometimes a yellowish gray, oftener light 

 brown; the throat and upper part of the breast usually darker 

 than the belly. The muzzle is covered with short, blackish hairs. 



The ears are of moderate length, reaching to the level of the 

 nostrils when laid forward; anterior edge distinctly thickened and 

 the whole ear conch very thick and leathery; anterior edge convex 

 its whole length ; posterior concave just below the broadly rounded 

 tip ; tragus rather short and blunt at tip. The membranes are 

 thick and blackish. The forearm and fingers are paler on the un- 

 der side and contrasting strongly with the membrane. Calcar 

 about equal to free edge of interf emoral membrane and, like the 

 limbs, rather strong. Wing membrane arising from the base of 

 the toes ; interf emoral from the tarsus. 



Measurements. — Adult male from Mitchell : Total length, 107 

 mm. (41/4 in.) ; tail, 47 mm. (1 14/16 in.) ; hind foot, 11 mm. 

 (7/16 in.) ; forearm, 45 mm. (1 13/16 in.) ; ear, 11 mm. (7/16 in.). 



Skull and teeth. — The skull (fig. 31) is very large and flat; the 

 braincase is somewhat wedge-shaped;, the interorbital constriction 



a b 

 Fig. 31. — Skull of Eptesicus fuscus : a, lateral view ; b, dorsal view. After Miller, 

 N. Am. Fauna No. 13, Bureau of the Biol. Sur., U. S. Dept. of Agri. 



is deep ; in old individuals there is a prominent median ridge which 

 divides at the interorbital constriction and rnns forward as two 

 fronto-maxillary ridg(;s. Tlicrc^ is ;i inarkcd d(^i)rcssi()n on either 

 side of the median line of the rostrum; braincase Hat. The jaws 



