22 LLOYD'S NATURAL HISTORY. 



The typical Bats have a cosmopolitan distribution, so far as 

 the temperate and tropical regions of the world are concerned. 

 The majority of the species are included in the two genera, Ves- 

 per tilio and VesperugO) and although the more typical representa- 

 tives of each of these are markedly distinct from one another, 

 yet there are certain intermediate forms which connect them 

 so closely, that their definition is a matter of some difficulty. 

 Under these circumstances, the obvious course would be to 

 unite the two genera, were it not that the number of species is 

 so great that, if this plan were adopted, each genus would be in- 

 conveniently large and unwieldy. 



THE LONG-EARED BATS. GENUS PLECOTUS. 

 Plecotus, Geoffr., Descript. de 1'Egypt. p. 112 (1812). 



Crown of the head flat, or only slightly elevated above the 

 line of the face ; upper incisor teeth closely approximated to 

 the canines, and thus widely separated in the middle line. 

 Ears very large, with the inner margins united at the base, and 

 the outer borders severally terminating behind the angles of 

 the mouth ; earlet, or tragus, very long, narrow, and tapering. 

 Nostrils placed at the extremity of the muzzle, in form elon- 

 gate, narrow, and crescentic ; upper surface of muzzle hairy, 

 flat and depressed in the middle line, but swollen and elevated 

 at the sides sometimes to such a degree as to form a roof 

 behind the nostrils over the middle region ; no grooves in the 

 front of the muzzle below the nostrils. Two pairs of both 

 incisor and pre-molar teeth in the upper jaw; and three of the 

 latter in the lower. 



There are but two species of Long-eared Bats, one of which 

 is an Old World, and the other a North American form. 



THE LONG-EARED BAT. PLECOTUS AURITUS. 



Vespertilio auritus t Linn., Syst. Nat. ed. 12 vol. i. p. 47 

 (1766). 



