THE FAMILIES AND GENERA OF BATS. 



211 



Genus HESPEROPTENUS Peters. 



18(iS. Heftperoptcmis Peters, Monatsber. k. preuss. Akacl. Wissensch., Bei- 



lin, ii. (S26 (subgenus of Ycsttcrua). 

 1878. Hexiicroptenus Dobson, Catal. Chiropt. Brit. Mus., p. 183 (subgenus 



of \'cni>crugo). 



Type-species. — Vesperus dories Peters. 



Geographic distribution. — India and the Malay region. 



Number of forms. — Three species of Ilesperoptenus are now 

 known: II. dorm (Peters), //. tickelli (Blyth), and II. Uanfordi 

 Dobson. 



Characters. — Dental formula and general structure of teeth as in 

 Eptesicus and Vespertilio ; 

 but outer upper incisor much 

 larger, the area of its base 

 more than half that of ca- 

 nine, which tooth, in its sim- 

 ple, strong shaft and well- 

 developed cingulum, it rather 

 closely resembles; space be- 

 tween inner incisor and ca- 

 nine scarcely perceptible, 

 barely greater than width of 

 cingulum of canine; outer 

 upper incisor closely crowded 

 between canine and inner in- 

 cisor, forced backward from 

 the toothrow, and quite in- 

 visible from the front; its 

 crown scarcely reaching level 

 of cingulum of the two 

 neighboring teeth, but with 

 area in cross section decid- 

 edly more than half that of 



inner incisor, the surface of the crown basin-shaped, with a large, but 

 low, central cusp ; other teeth like those of Eptesicus, the third upper 

 molar with less than half the crown area of first, but with the meta- 

 cone and three commissures distinct though small. Skull (fig. 33) 

 broad, the zygomatic breadth nearly equal to upper length in median 

 line, but with no special peculiarities in form; basisphenoid pits 

 well developed, though shallow. Externally as in Eptesicus. 



Species examined. — Ilesperoptenus tickelli (Blyth). 



Remarks. — It is with some hesitation that I apply the name Iles- 

 peroptenus to the genus represented by II. tickelli. I have not seen 

 "Vesperus " doricc, the type of Ilesperoptenus, and certain features 

 in the original description, notably what is said of the position of the 



FIG. 33.— HESPEROPTENUS TICKELLI. CEYLON. No. 123437 



