1918] Grinnell: A Synopsis of the Bats of California 363 
An example (no. 19006, 2) from Concord, Contra Costa County, 
presents what is apparently the usual coloration of the species in 
California. This specimen is hair brown in color, slightly paler 
beneath, and with feet and membranes varying toward chaetura 
black. The hairs on the body are everywhere whitish at their bases. 
The long scattered hairs upon the face and chin are a dark hair 
brown, while the long curved hairs upon the dorsal surface of the 
claws are whitish. 
Several specimens from Los Banos, Mereed County, and the two 
examples from Painted Rock, Carrizo Plains, San Luis Obispo 
County, exhibit a yellowish suffusion, due perhaps to absorption of 
oil from the skin. Among thirty-one specimens from the vicinity 
of Fresno, Fresno County, a single example shows marked departure 
from the normal coloration. This individual is unusually sooty in 
appearance, fur and membranes being chaetura black in color. 
Skull—Brain-ease slightly rounded; sagittal crest very feebly 
developed ; lachrymal and supraorbital ridges low but distinct; dorsal 
surface of rostrum with a shallow longitudinal median coneavity ; 
zygomata slightly expanded at middle. Dorsal profile nearly straight, 
rising gradually from nose to top of brain-case; a depression between 
top of brain-case and occipital ridge. (See pl. 23, fig. 48; pl. 24, 
fig. 56). 
= = = 9) OL 
Teeth.—Dental formula: is ory s os, pm 99° m 54 = 30 or 
32. Upper incisors simple, well developed, about half as high as 
canines, wide apart at base, strongly converging at tips, separated 
from canines by a space about equal to their greatest diameter, shaft 
narrowing both above and below slightly developed cingulum, its 
apex blunt. First and second lower incisors equal, their crowns in 
contact with each other and with cingulum of canine. In young 
specimens the crowns are bifid, with lobes rounded at the tip. In 
old specimens the crowns are squarely truncated; in some all trace 
of the notch is obliterated. Third incisor when present varies from 
a mere spicule to a slender well-formed tooth, bifid at crown, and 
three-fourths height of second incisor. In a series of thirty-seven 
skulls belonging to the Museum of Vertebrate Zoology sixteen were 
found to have three lower incisors on each side, eight to have two 
only, four to have two in the right mandibular ramus, and three in 
the left, and two to have three in the right ramus and two in the left. 
Seven of the skulls were found to have less than four lower incisors, 
the ones present being badly worn and broken. 
Stowell (1894, p. 363) found that of forty-five specimens examined 
twenty-four possessed six lower incisors, nine had five, and twelve 
had four. He remarks: 
The outer incisor when present is very small, and so crowded forward as to 
occupy a precarious position in front of the canine, a fact which may account 
for its absence in so many specimens. In by far the majority, the incisors are 
distinctly bilobate and the lobes have well-rounded tips; but in some specimens 
the tips have become more or less worn, and in a few individuals this process 
has proceeded so far that the upper edges of the teeth are truncate, with scarcely 
a trace of the median notch. In the specimens examined we have noticed that 
most of those with perfectly truncate incisors have the latter also reduced in 
number. This probably indicates that both conditions are dependent upon age. 
