1918] Grinnell: A Synopsis of the Bats of California 349 
tinct horseshoe-shaped ridge above each nostril (text-fig. U) ; behind 
this, a large flattish swelling on each side. Ears separate and wide 
apart at bases, extending considerably beyond tip of muzzle when laid 
forward (pl. 17, fig. 11). Tragus slender, straight and long, half 
leneth of ear. Whole posterior border of tragus faintly crenulate; a 
well-developed lobe at posterior base. 
Limbs and Membranes.—Wing short and broad; third metacarpal 
but slightly longer than fifth. Lateral membrane attached at bases 
of toes. Tip of tail exserted beyond interfemoral membrane. Length 
of calear somewhat less than half that of free border of interfemoral 
membrane. Feet broad and strong, about half as long as tibia. 
Claws large and strong; chord of exposed portion of each claw about 
2.5 millimeters long. 
Pelage—¥F ur on back silky, and about 8 millimeters in length. 
Fur on ventral surface shorter, averaging about 5 millimeters in 
leneth, and more abundant. Wing and tail membranes not furred 
except at their extreme bases. A narrow strip of hairs on dorsal 
surface of anterior border of ear, extending outward to about middle 
of border, and diminishing in width as it advances. On ventral sur- 
face of ear, lines of hair extend along two ridges which run parallel 
with anterior border of auricle. A few short hairs on backs of toes. 
Color.—Hairs on back very pale drab gray, tipped on terminal 
fourth with pale brown. On under surface of body the hairs are 
erayish white, and toward sides of body suffused with a pale yellowish 
tint. Ears light brownish, wing membranes and feet darker. 
Skull—Greatest length varies from 19.4 to 21.0 millimeters. 
Brain-case, rostrum, and palate, broad. Length of bony palate 
behind molars (exclusive of median spine) slightly less than its width 
at base of median spine. Dorsal profile unevenly convex. Rostrum 
more than half as long as brain-ease. Auditory bullae covering nearly 
the entire cochleae; their greatest diameter equal to twice the distance 
between them. (See pl. 23, fig. 55; pl. 24, fig. 63.) 
Teeth—Dental formula: 1 ea) at pm = m = —— 8 Upper 
incisor large and simple, its shaft more than half as high as canine. 
Posterior basal lobe of incisor in contact with cingulum of canine. 
Lower incisors somewhat crowded; their trilobed crowns strongly 
imbricated. »- Upper and lower canines about equal in length, but 
former twice as wide at base as latter; cingula of both distinct but 
small. Upper premolar transversely long and narrow. First lower 
premolar small and narrow, closely wedged between canine and 
second premolar; latter equals first lower molar in height. First and 
second upper molars with middle cones highest. Third upper molar 
with less than half crown area of either of others, its outer cone 
highest. Lower molars with outer cusps much higher than inner. 
Measurements—Average and extreme measurements in milli- 
meters of a series of eight specimens in the Museum of Vertebrate 
Zoology are as follows: Three males, total length, 104.0 (extremes, 
99.0-111.0) ; tail vertebrae, 42.3 (40.0-47.0) ; tibia, 18.9 (18.4-19.4) ; 
foot, 11.8 (11.0-12.0) ; forearm, 47.4 (46.8-48.4) ; greatest length of 
skull, 19.7 (19.4-20.2) ; five females, total length, 112.3 (103.0-122.0) ; 
