128 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



Characters. — In general not unlike Micronycteris, but ears separate 

 and tail longer than femur, continued to outer edge of broad inter- 

 femoral membrane. Skull with short rostrum, its length less than 

 breadth of bra incase; nares emarginate laterally and above, leaving 

 a noticeable flattish area over roots of incisors; basioccipital pits 

 obsolete; audital bulla? small, not covering half of cochleae. Teeth 

 essentially like those of Micronycteris, except that middle lower pre- 

 molar (pm 3 ) is minute and so crowded inward that first and third 

 are almost in contact, first upper premolar (pm 3 ) is not much larger 

 than outer incisor, middle upper incisors project more conspicuously, 

 and lower incisors have the crowns relatively wider. 



Species examined. — Dolichophyllum macrophyllum (Wied). 



Genus TONATIA Gray. 



1827. Tonatia Gray, Griffiftn's Cuvier, Animal Kingdom, V, p. 71 (Vam- 



pyrus bidens Spix). 

 1836. Lophostoma d'Obbigny, Voyage dans 1'Amerique merid., pi. vi {syl- 

 , vicola=aml)lyotis according to Dobson). 



1878. Lophostoma Dobson, Catal. Chiropt. Brit. Mus., p. 473. 

 1891. Lophostoma Flower and Lydekkee, Mammals living and extinct, 

 1 p. 673. 



1898. Tonatia Palmer, Proc. Biol. Soc. Washington, XII, p. 110, April 30, 

 1898. 



Type-species. — Vampyrus bidens Spix. 



Geographic distribution. — Tropical America, from Brazil to 

 Panama. 



Number of forms. — Four forms of Tonatia are now recognized. 

 Characters. — Dental formula : 



-2 3. 1. --34 567 -2-2 1-1 2-2 3-3 



1--. 1.-23456 7 * 1=1' ° 1=1' P 171 3=3' m 3=3 =32 ' 



Teeth throughout more robust than those of Micronycteris, though 

 not essentially different in structure. Inner upper incisors with 

 lower, longer, more obliquely set crowns than those of Micronycteris, 

 the posterior face more strongly concave and outer posterior border 

 in contact with canine. Outer incisor crowded forward, completely 

 filling angle between canine and inner incisor, its anterior surface 

 nearly half as extensive as that of inner tooth. Lower incisor dis- 

 tinctly higher than wide, the anterior surface slightly concave, but 

 cutting edge not distinctly emarginate. Canines showing no pecu- 

 liarities except that the lower are in contact posteriorly. Cheek 

 teeth essentially like those of Micronycteris except that anterior upper 

 premolar is much broader than long and middle lower premolar is 

 minute and quite functionless, crowded between the anterior and 

 posterior teeth and not rising to level of cutting surface. First and 

 second upper molars with small but distinct hypocone. Skull like 

 that of Micronycteris, but not as lightly built. Zygoma with abrupt 



