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 braincase; nares emarginate laterally and above, leaving 
a noticeable flattish area over roots of incisors; basioccipital pits 
obsolete; audital bullse 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, Griffith’s Cuvier, Animal Kingdom, V, p. 71 (Vam- 
pyrus Widens Spix). 
1836. Lophostoma d’Orbigny, Voyage dans l’Amerique merid., pi. vi (syl- 
I vicola=amhlyotis according to Dobson). 
1878. Lophostoma Dobson, Catal. Chiropt. Brit. Mus., p. 473. 
1891. Lophostoma Flower and Lydekker, Mammals living and extinct, 
i p. 673. 
1898. Tonatia Palmer, Proc. Biol. Soc. Washington, XII, p. 110, April 30, 
1898. 
Type-species. — V ampyrus 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. --34567.2-2 1-1 2-2 3-3 
1--. 1, - 234567 A - 1’ 0 1-V P m 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 
