﻿70 



NORTH AMERICAN FAUNA. 



Ears moderate, reaching just beyond tip of nose. Wings from base of 

 toes. Fur on back distinctly darker at base than at tip. 



Uars. — The ears are moderately long (PI. T, fig. 2), reaching when laid 

 forward 1 to 3 mm. beyond tip of nose. The anterior border of the 

 auricle is straight or slightly convex at the base, then strongly convex 

 to a point somewhat beyond the middle, after which it is straight or 

 even a little concave to the narrowly rounded olf tip. Posterior border 

 concave from tip to i)oint slightly below the middle, after which it is 

 convex to basal notch. Basal lobe strongly developed and notched on 

 its lower border. 



Tragus varying much in shape, but with anterior border usually 

 straight, or nearly so, and posterior border strongly convex and with 

 small basal lobe. 



Membranes. — The membranes are thin and delicate. Uropatagium 

 (PI. II, fig. 1) furred on basal third, otherwise naked, except for a few 

 hairs along the veins. Wings from base of toes, naked, except for a 

 narrow strip along side of body. 



Feet. — The feet are small and weak (PI. II, fig. 1), distinctly less than 

 half as long as tibia. Oalcar slender but distinct, shorter than free 

 border of uropatagium, usually terminating in a distinct lobule. The 

 posterior border is provided with a k^eel beginning abruptly about 2 

 mm. from the base and fading away gradually at about middle of calcar. 

 This keel is supported by 1 to 3 cartilaginous outgrowths from the 

 calcar. 



Fur and color. — The fur is soft, full, and long, that on middle of back 

 averaging about 8 mm. in length. 



Color light yellowish gray, paler on the belly, the fur everywhere 

 dark plumbeous at base. Membranes, ears, lips, and muzzle blackish. 



Shull. — The skull of Myotis californicns is smaller and more lightly 

 built than that of any other North American Myotis. The brain case 

 is moderately rounded, and the long narrow muzzle fades gradually 

 into the gently sloping forehead. The skull is thus very different from 

 that of M. yumanensis, the only sj^ecies with which M. californicns is 

 likely to be confused. In form it resembles the skulls of M. evotis 

 and ill. thysanodes, but the latter are among the largest of the species 

 found in the region inhabited by ill. californicns. 



Teeth. — The teeth of Myotis californicus (fig. 15, a) are, like the skull, 

 small and delicate. In general they closely resemble the teeth of M, 

 snhulatus^ and differ from those of M. yumanensis in numerous details, 

 as in the shape of the third upper molar and third lower j)remolar, the 

 former being distinctly narrower and the latter longer in i^roportiou to 

 its width than in M. yumanensis. 



Measurements, — See table, i)age 74. 



Specimens examined. — Total number 152, from the following localities: 



Arizona: Camp Grant, 2; Oracle, 5; Prescott, 1 (skin, Am. Mns. Nat. Hist.); 

 Santa Catalina Mountains, 1 (slciu) ; Tinajas Altas, Yuma County, 3; White 

 Mountains, 1 (skin, Am. Mus. Nat. Hist.). 



