316 University of California Publications in Zoology  [Vou.17 
Diagnosis.—Size medium (total length 107 to 122 millimeters) ; . 
ear about 18 millimeters in height, its width slightly less than two- 
thirds of height; tragus two-thirds height of ear, tapermg, and 
directed slightly forwards. Color, varying dorsally from raw umber 
to vandyke brown, ventrally from pale wood brown to light bister. 
Description: Head.—Muzzle short and broad, greatest width of 
rostrum almost equaling its length. Nostrils elliptical in shape and 
directed outward and slightly downward; region between them 
slightly coneave. Hye small and inconspicuous and situated above 
posterior angle of mouth. A tumid, glandular area, some three or 
four millimeters in width, occupies entire space between nostril and 
eye on each side of head and adds to apparent width of rostrum, Ear 
short, reaching barely to nostril when laid forward. (See pl. 18, 
fig. 13.) 
Limbs and Membranes.—Wing short and broad (text-fig. E), 
length of fifth metacarpal almost equaling that of third. Wing 
membrane attached to foot a little beyond bases of toes. Free edge 
of interfemoral membrane a little shorter than calear and terminating 
at base of next to last caudal vertebra. Foot more than half length 
of tibia. Calear slightly longer than foot, keeled on its outer edge, 
and terminating in a faintly defined lobe. 
Pelage—F ur everywhere full and soft; on dorsal surface of body 
about 7 millimeters in length, on ventral surface slightly shorter. 
Ears furred only on basal third of outer surface; scantily sprinkled 
with hairs over most of inner surface, these hairs being most numerous 
near anterior border of auricle. Dorsal surface of wing naked, save 
for narrow strip of fur continuous with fur of body. Ventral surface 
of wing membrane furred in a manner similar to that of dorsal sur- 
face. Interfemoral membrane furred only at its extreme base above; 
but below, scattering hairs extend almost to tip of tail. Toes scantily 
clothed, both above and below, with very fine, short hairs. 
Color.—The color varies considerably, skins from even a single 
locality exhibiting a wide range. An average condition of coloration 
is shown by a brown bat taken at Kenworthy, in the San Jacinto 
Mountains, in May, 1908, as follows: above, bases of hairs dark seal 
brown, their distal two-thirds raw umber; hairs on throat pale wood 
brown; rest of fur-on lower surface pale seal brown on basal half, the 
distal half pale wood brown. Ears and membranes blackish. 
Skull and Tecth—As deseribed for the genus. 
Measurements—Average and extreme measurements in milli- 
meters of a series of ten brown bats in the Museum of Vertebrate 
Zoology are as follows: five males: total length, 109.8 (extremes 
107.0-112.0) ; tail vertebrae, 43.8 (38.0-47.0) ; tibia, 16.9 (16.0-17.5) ; 
foot, 9.0 (8.0-10.0); forearm, 44.1 (43.8-44.9); greatest length of 
cranium, 18.3 (17.9-18.8) ; five females: total length, 116.1 (110.0- 
119.0) ; tail vertebrae, 45.3 (43.0-48.0) ; tibia, 17.3 (16.4-18.0) ; foot, 
10.0 (9.0-12.0) ; forearm, 46.2 (42.9-49.0) ; greatest length of skull, 
19.0 (18.8-19.4). 
A comparison of the above figures will show that the females aver- 
age somewhat larger than the males. 
