THE FAMILIES AND GENERA OF BATS. 123 



Inner upper incisor not chisel-shaped, the front face of 



the two teeth together strongly convex or biconvex ; 



second upper premolar with distinct style and with 



the main cusp at middle of crown, its apex straight. 



Crown of inner upper incisor longer than wide ; 



lower incisor row concave posteriorly. 



Micronycteris, p. 123. 

 Crown of upper incisor wider than long ; lower 

 incisor row convex posteriorly. 



Xenoctenes, p. 124. 

 Middle lower premolar much smaller than third. 



First lower premolar in contact or nearly so with third, the 

 second displaced inward from the tooth row. 



Length of rostrum much less than breadth of brain- 

 case Dolichopliyllum, p. 127. 



Length of rostrum about equal to breadth of brain- 

 case Trachops, p. 132. 



First lower premolar distant from third, the second in 

 tooth row. 



Dorsal profile of rostrum strongly convex ; a deep 



depression between orbits Lonchorhina, p. 127. 



Dorsal profile of rostrum not convex ; no depression 

 between orbits Phylloderma, p. 131. 



Genus MICRONYCTERIS Gray. 



1856. SchizostOma Gebvais, Bxped. du Comte de Castelnau, Zool. Mamm., 



p. 49. Not of Bronn, 18.35. 

 1862. Schizastoma Gray, Catal. Bones Mamm. Brit. Mus.. p. 38. 

 1866. Micronycteris Gbay, Proc. Zool. Soc, London, p. 113. 

 1872. Vampyrella Reinhaedt, Vidensk. Meddelelser, Naturhist. Forening 



Kjobenhavn, IV, p. ill. Not of Cienkowsky, 1865. 

 1878. Schizostoma Dobson, Catal. Chiropt. Brit. Mus., p. 476. 

 1891. Micronycteris Lydekker in Flower and Lydekker, Mammals, living 



and extinct, p. 673. 

 1906. Micronycteris Andebsen, Ann. and Mag. Nat. Hist., 7th ser., XVIII, 



p. 50, July, 1906. 



Type-species. — Micronycteris megalotis Gray. 



Geographic distribution. — Warmer parts of the American main- 

 land north to central Mexico. 



Number of forms. — Four forms of Micronycteris are now recog- 

 nized : M. megalotis Gray, M. m. mexicanus Miller, M. microtis Miller, 

 and M. minuta Gervais. 



Characters. — Dental formula (Plates III-IV, fig. 1) : 



-2 3. 1. --34567 . 2-2 1-1 2-2 3-3 



1 2 -. 1. - 2 3 4= 5 6 7 * 2 - 2' C 1- V pm 3-3' m 3 - 3 -34 - 



Upper incisors very unequal, completely filling space between ca- 

 nines. The inner tooth is large, the crown at least twice as high as 

 wide, slightly projecting and somewhat oblique, so that the middle 

 pair of teeth are strong^ in contact distally, though the roots are 

 rather wide apart; cutting edge faintly divided by notch near outer 



