92 MAMMALIA—BAT. 
Their motion in the air is with less propriety to be termed a flight, than 
a kind of uncertain flutter, which they seem to execute by struggles, and in 
an awkward manner. ‘They raise themselves from the ground with difficul- 
ty, never soar to a great height, and are but imperfectly qualified to accele- 
rate, or even to direct, their flight. This, far from being either rapid or 
very direct, is performed by hasty vibrations in an oblique and winding 
direction; and in passing along they do not fail to seize all the gnats, moths, 
and other nocturnal insects that come in their way. These they swallow 
entire; and in their excrements we meet with the remains of wings and 
the other dry parts, which they have not been able to digest. Like quadru- 
peds, the bat brings forth its young alive, and like them it has teeth 
and nipples. 
From the observations of Spallanzani, 1t appears that many of the bats 
possess an additional sense, by which, when deprived of seeing, they are 
enabled to avoid any obstacles that may be in the way of their flight. 
It is affirmed that these animals do not produce more than two at a birth, 
and that these they suckle, and even carry along with them as they fly. 
They unite in numbers to defend each other from the cold; they pass the 
winter without awaking, without stirring, and without eating, from the end 
of autumn till spring. Though they can more easily support hunger than 
cold, and can even subsist a number of days without food, they yet belong 
to the number of carnivorous animals; for, when opportunity serves, they 
will devour bacon, and meat of all kinds, whether raw or roasted, whether 
fresh or corrupted. * 
VAMPIRE BATS. 
Dae ROUsS flies TA E BOGE ET EB 2 AND 
TEE! (S Pe, CT. RE, BAL. 
Tue roussette and the rougette seem to form two distinct species, which, 
however, are so full of resemblances to each other, that they ought not to 
be presented asunder. The latter differs from the former solely in the size 

1 Pteropus vulgaris, Georr. The genus Pteropus has four upper and four lower incisors; 
two upper and two lower canines ; ten upper and twelve lower molars. Molars with the 
crown truncated obliquely, and marked with a longitudinal furrow; head, long and 
conical; ears short, simple, with auricles; no crest or nasal appendage; tail short,or none; 
interfemoral membrane sloped off. An additional phalanx and nail on the index finger 
of the wings; tongue papillous. 
2 Pteropus stramineus, GEOFF. 
3 Phyllostoma spectrum, Lix. The genus Phyllostoma has four upper and four lower 
incisors ; two upper and two lower canines ; ten upper and ten or twelve lower molars. 
Lateral incisors very small, the intermediate ones feaier; head, long and conical ; nose 
with two nasal crests, one like a leaf, the other of a horse-shoe form; ears large, naked, 
not united. Auricle internal, dentated ; eyes small and lateral; tongue rough with horny 
papillee ; tail and interfemoral membrane more or less developed. 
