476 ZOOLOGY. 
chinks or fissures of a rock, it can climb and crawl about with great facility. 
The air, however, is its home, and through this it moves with considerable 
swiftness, and with great apparent ease, wheeling in every direction, and 
performing the most abrupt evolutions in search of its insect prey. In 
these movements it is very much assisted by the tail, which serves as a 
rudder; and we shall find that this organ is most developed in bats which 
pursue insects on the wing, whilst it is small, or entirely wanting, in those 
which live on fruits. In their mode of flight, bats bear a very strong 
resemblance to swallows, which like them pursue insects on the wing; but 
whilst the latter seek their food during the day, the former come forth only 
at twilight. During the day the bats sleep in their recesses, suspended by 
their hind feet, their heads consequently hanging downwards; and they 
assume the same position during the whole winter, which in the temperate 
zone is passed by them in a state of torpidity. 
The bats may be divided into two sections: the carnivorous or insectivo- 
rous, and the frugivorous. 
Group 1. Carnivora or Insectivora. 
The insectivorous or insect eating bats are by far the most numerous of 
the order; they possess a dentition and a digestive system in accordance 
with their particular kind of food. The molars are beset with pointed 
tubercles, adapted to crush the hard envelopes of insects; the canines are 
sometimes of a large size. The intestinal canal is much shorter than in the 
frugivorous tribe. 
The insectivorous bats are subdivided into several families, the number 
of which is variable according to the views of systematic writers. Some 
adopt five or six; we only two: the Vampyride and Vespertilionde. 
The bats existed during the tertiary epoch, and have left some of their 
remains in the deposits of past ages. As far as hitherto known, they belong 
to the family of Vespertiliontide. The frugivorous bats are not yet known 
to have existed prior to our days. We must, however, expect many 
discoveries to be made in the extinct fauna of this singular order of 
animals. 
Fam. 1Vampyripaz. The genus Dysopes or Molossus (bull-dog bats) 
belongs both to the old and new world. The snout is simple; the ears 
are broad and short, arising near the angle of the lips, and uniting with 
each other on the snout. The tail occupies the whole length of their 
inter-femoral membrane, and most generally even extends beyond it. T'wo 
species of this genus are found in the southern United States. The fossil 
remains of one species have been discovered in the Brazilian caverns. 
The genera Dinops, Nyctinomus, and Cheiromeles, are mere subdivisions of 
this genus. 
The genus Diclurus (fox-tailed bats), nearly related to the preceding, 
contains but one species, from tropical America. | 
The genus Noctilio (hare-lipped bats) is distinguished by a short snout, 
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