CHEIROPTERA. 131 



upper incisors, by their length and position, appear 

 like a second pair of canines. 



There is as yet only one species known, namely, 

 Nyctophiltu Geoffroyi^ with hair black at the root, 

 and pale ash at tip; it is three inches long, and 

 nine across the wings. 



Genus NYCTERIS, Cuv. Cheek-pouch Bats. 

 Dent. form, incis. f, can. \-\, mol. T % = ^f =32. 

 Upper incisors very small, continuous, and bilobed ; 

 the lower trilobed or bilobed ; nostrils simple, the 

 cartilage forming a moveable operculum ; the chaff- 

 ron with a deep longitudinal furrow; interfemoral 

 membrane longer and wider than the body; tail 

 bifurcated at tip. This genus, according to Geoffroy, 

 has the power of inflating the tissues of the skin, 

 by means of two passages communicating with the 

 mouth, thereby rendering itself, like birds, speci- 

 fically lighter. The different species are found in 

 the warm regions of the Old World, where they 

 frequent dark and nauseous caverns. 



Nycteris hispida was known to Buffon, and is 

 the Campagnol volant of Daubenton. There are 

 enumerated five other species. 



Genus DESMODUS, P. Max. of Wied. Curved 

 Tooth Bats. Dent. form, incis. f , can. \-\, mol. f 

 = i 8 ? = 20. Head small ; muzzle obtuse ; ears 

 with opercula ; nose with complicated membranes ; 

 thumbs very long and strong; interfemoral mem- 

 brane narrow ; tail none. This genus is still one of 

 the blood-suckers, for it was an individual of the 

 Desmodus d'Orbignyi that Mr. Darwin's servant 



