168 



VF.SPEETILIONIDJ!. 



The Vespertilionidas are easily distinguished from other Bats by 

 their simple nostrils terminating the conical moderately elongated 

 muzzle, by the long tail produced to the hinder margin of the large 

 interfemoral membrane, and by the upper incisors, which are sepa- 

 rated by a wide space and placed near the canines. Their eyes are 

 minute ; and the inner margins of the ears arise from the sides of 

 the head, not from the forehead. 



Distribution. Generally distributed throughout the temperate and 

 tropical regions of both hemispheres. 



Synojasis of the Genera. 



A. Crown of the head flat or slightly raised 

 aboTe the face-line ; upper incisors 

 close to the canines. 



a. Nostrils margined behind by rudimen- 



tary nose-leaves, or by grooves on 

 the upper surface of the muzzle ; 

 eai-s generally very large ; forehead 



grooved Group I. PLECOTI. 



a' . A small or rudimentary nose-leaf 

 above the nasal apertures ; inci- 



1—1 1—1 

 sors -^ or -g-. 



a". Incisors ^j^ ; margins of the 

 nasal apertures continuous with 

 the rim of a small disk above ; 

 ears separate 1. Antbozous, p. 170. 



h" . Incisors -g-; a small nose-leaf 

 above and behind the nasal 



apertures ; ears united 2, Nyctophilus, p. 171. 



6'. No nose-leaf; nostrils in front of 

 -' grooves on the upper surface of 



the muzzle ; ears very large. 



fi''- Incisors —^ ; ears united. 



c'". Premolars guj; outer margin 

 of the ear-conch carried for- 

 wards above the mouth and 

 in front of the eye 3. Synotus, p. 175. 



2 2 . 



d'". Premolars giig ; outer margin 

 of the ear-conch terminating 

 near the angle of the mouth . 4. Plecotus, p. 177. 



d". InciSors^-; ears separate. 

 «'". Premolars 2E2 ; outer margin 

 of the ear-conch terminating 

 near the angle of the mouth . 6. Otonyctbeis, p. 181. 



b. Nostrils simple, opening by cre- 



scentic or circular apertures at the 

 extremity of the muzzle ; ears 

 generally moderate ; forehead not 



grooved Group II. VESPERTILIONES. 



b'. The outer margin of the ear-conch 



