268 BATS. 



band at their bases, wliicli in some sjjecies is so slightly develoj)eil as to be almost 

 invisible. Moreover, these bats have well-developed tails, and also upper incisor 

 teeth, the total number being 32, of which 5 on each side are incisoiTi, \ canines, 

 and ^ cheek-teeth. So different, indeed, are the bats of the genus Xyderis from the 

 false vampires, that the reader might well wonder wliy tlie two are associated in a 

 single family. There are, however, important resemblances in the form and structure 

 of the head and skull, among which — as characters visible externally — maj^ be men- 

 tioned the pointed and cylindrical muzzle, and the projection of the lower jaw beyond 

 tlie upper ; these being sufficient to establish the near relationship of the tM'O groups. 

 With the exception of one species {X. javanica) from Java and the Malay 

 Peninsula, the bats of this genus are confined to Africa, where they are mostly 

 restricted to the regions south of the Sahara, although one of them ranges into 

 Egypt. 



The Typical Bats. 



Family VeSPERTILIONID^. 



With the exception of the horseshoe-bats already described, the whole of the 

 bats found in the British Islands, and, indeed, in Europe generally, may be included 

 in a single family, which may conveniently be designated popularly as the typical 

 bats, and is scientifically known as the Vespertilionida;. All these bats agree with 

 the two preceding families in the relation of the tail to the membrane between the 

 legs ; but they are distinguished by tiie absence of a distinct nose-leaf, the nostrils 

 merely forming circular or crescent-shaped apei-tures at the end of the muzzle 

 without any complications from foldings of the skin. Their tails are long, and 

 produced to the edge of the membrane between the legs : ami their ears are always 

 furnished with a distinct tragus. Apart from certain details in the stnicture of 

 their skulls which need not be mentioned here, it may be observed that the incisor 

 teeth of the upper jaw are alwaj's of small size, those of opposite sides being 

 separated from one another by a considerable interval, while their number varies 

 from one to two pairs. The lower incisor teeth, on the other hand, are, with 

 one exception, three pairs. Moreover, there are generally either six or five cheek- 

 teeth on each side of both upper and lower jaws, the reduction in number in the 

 latter instance being due to the disappearance of one of the premolars. 



In addition to being the common bats of Europe, the typical bats have an almost 

 world-wide distribution, and include more than one hundred and fifty di.stinct specie.s. 

 The absence of the uose-leaf, together with other features in their organisation, 

 indicates that they are less .specialised tj'pes than the two precetling families, to 

 which, however, they are in other respects intimately related. Accordingly, 

 Dr. Dobson considers that in the tj'pical bfits we have the descendants of the 

 ancestral forms Avhich gave rise both to the Nycti'vuhi; and the horseshoe and 

 leaf-nosed bats ; and we may thus regard all these three families as forming a 

 single distinct branch of the insectivorous bats ; the main stem of this branch being 

 formed by the Vespertilionidce, and the otlier two families forming side branches. 

 The number of these bats being so great, all that can be done here will be to 

 select a few of the better-known examples of some of the more important genera. 



