﻿MYOTIS THYSANODES. 



81 



JEars. — The ears (PI. 1, fig. 5) are moderately long and obtusely 

 pointed j laid forward they reacli 3 to 5 mm. beyond the tip of the nose. 

 Anterior border of auricle straight or slightly convex through basal luilf, 

 then more convex for a short distauce, after wliich it is nearly straight 

 to the rounded tip; posterior border at first straight or slightly con- 

 cave, sloping rapidly backward to the widest point at about mid-height, 

 below which the border becomes convex and continues so to the well- 

 marked basal notch. Basal lobe distinct and moderately large. 



Tragus long and slender, the anterior border straight or slightly con- 

 cave at base, then straight or slightly convex to near the tip, just below 

 which the border is always convex. Posterior border with a well- 

 developed lobe at base, widest part of tragus through this lobe or 

 immediately above it. A more or less developed notch above the lobe. 

 Beyond this notch the border is at first strongly convex, then slightly 

 concave below the tip, which is thus always bent backward. Posterior 

 border indistinctly crenulate. 



Membranes. — The membranes are moderately thick arid dark colored. 

 Uropatagium noticeably more leathery than wing membranes, distinctly 

 thickened at free edge, sparsely haired on proximal fourth both above 

 and below, the rest of the membrane with a few scattered hairs, which 

 become njore abundant toward the free border, where they form a con- 

 spicuous fringe both above and below (Pi. II, fig. 5). Wing from side 

 of foot, just below base of toes. 



Feet. — Feet (PI. II, fig. 5) large and strong, half as long as tibi;B. 

 Toes (without claws) slightly longer than sole, scarcely united by mem- 

 brane at extreme base; all sparsely haired. Oalcar distinct and thick, 

 considerably longer than free border of interfemoral membrane, termi- 

 nating distinctly, but usually without well-developed lobule. 



Fm- and color. — There is nothing peculiar in the distribution of the 

 fur in this species, except the thickly haired border of the uropatagium. 



In color the fur is everywhere light, dull, yellowish brown, distinctly 

 paler ventrally, the hairs everywhere dusky slate at base. The color 

 is subject to considerable individual variation in shade. The palest 

 specimens are yellowish wood brown inclining to clay color ; the darkest 

 specimens dull raw umber. The belly varies from clear gray scarcely 

 tinged with yellow to a strong yellowish gray, and in other specimens to 

 dull brownish gray. The exact shades are very variable and impossible 

 to describe accurately. 



81mU. — Skull (tig. 11 Z>, and fig. 12 h) large, exactly the same size as 

 that of M. velifer, but more lightly built. Brain case oval in outline, 

 abruptly rounded posteriorly, occipital region inflated and lacking well- 

 formed ridges. Forehead moderately elevated above muzzle. Distance 

 from posterior border of last upper molar to tip of hamular greater 

 than width between alveoli of posterior molars. 



Although the skull of this species and that of M. velifer are equal in 

 size, that of the former is easily distinguished by its more inflated brain 

 2772— No. 13 0 



