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 apjoarent 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 tlie 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 laroe 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 Yampyrkke and Vesp)ertih'o7iidce. 



The bats existed during the tertiary epoch, and have left some of their 

 remains in the deposits of past ages. As flir as hitherto known, they belong 

 to the family of Vespertilionidai. 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. 1. Vampyrid^. The genus Dysopes or Molossm (bull-dog bats) 

 belongs both to the old and new world. The snout is simjDle ; 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. Two 

 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, Nyctinomiis^ and Cheiromeles, are mere subdivisions of 

 this genus. 



The genus Didurus (fox-tailed bats), nearly related to the preceding, 

 contains but one species, from tropical America. 



The genus Noctilio (hare-lij)j)ed bats) is distinguished by a short snout, 

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