114 
JOUENAL OF MAMMALOGY 
while the ones in the ventilators were continually stibjected to a cold 
draught, which may have rendered them torpid throughout a protracted 
period. When I secured these individuals, I surreptitiously pried loose 
a corner of the screening, and what was my delight, upon visiting the 
attic December 5, 1919, to find about seventy mastiffs in the gable. 
They were hung to the shingle studs beneath the sloping roof, a short 
row to a stud, and thus overlapping as if they were animated shingles — 
truly a sight to delight the heart of a mammalogist. I took a few of 
these and found that they were of both sexes, as usual. 
A colony was located in a small, two story house near my place on 
April 15, the bats gaining entrance through a slatted ventilator at the 
end of the attic. It was a very old roost and the guano was thick 
beneath it. There were seven mummified bodies upon the floor, I 
captured thirteen live ones, and there were at least eight or ten more 
in some cracks, but they were very lively, keeping up a great racket 
while scrambling about their retreat, and braced themselves so securely 
that it required much persevering manipulation with the long forceps 
to secure them. 
On March 18 we discovered a colony of thirteen mastiffs in the attic 
of a two story building near Azusa, Los Angeles County. From this 
we took ten. I visited this again on May 31 and took two females, 
but left a single male. At the other end of this attic was a colony of 
Nyctinomus and Eptesicus. When Little visited this spot in late Decem- 
ber there were no bats present. 
This species, like its near relative Nyctinomus, has a very penetrating 
odor — decidedly more so than that of most bats — and this will cling 
for months to a sack in which the animals have been carried. I have 
always found both sexes together, even just before young were to be 
expected, and the females outnumber the males by about two to one. 
The average measurements in millimeter^, taken by myself, of ten 
males and twenty-two females, are, respectively for the sexes — length, 
175 and 174; tail, 60.7 and 57 ; expanse, 540.7 and 526. 
The gland on the lower throat with its external opening is easily 
overlooked when inactive, and indeed I have been able to find no men- 
tion of it in publications. Ordinarily, it appears externally as a tiny 
dent, and internally, the skin is here attached to the body by a sort 
of tendon. When the males are most active sexually, the gland swells, 
is then shaped like a small-holed doughnut of a grayish, cheesy forma- 
tion, and measures 14 mm. in diameter by 4 in depth. This makes a 
corresponding swelling externally and the opening is much enlarged. 
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