134 BULLETIN 5 1, UNITED STATES NATIONAL MUSEUM. 
ized by the very large though simple ana separate ears (the middle 
of conch extends to nostril when laid forward) ; tail barely percep- 
tible in base of very wide interfemoral membrane; lips and chin 
nearly smooth ; fur unusually long and soft. 
Species examined. — Clirotopterus auritus (Peters). 
Remarks. — Though currently regarded as a subgenus of V ampyrus. 
this group is sufficiently well characterized to be recognized as a dis- 
tinct genus. As pointed out by Dobson, it is in many respects inter- 
mediate between Yampyrus and the more ordinary members of the 
subfamily. The structure of its teeth also places it in an intermedi- 
ate position, though nearer the more normal genera than to Yam- 
pyrus. 
Genus VAMPYRUS Leach. 
1821. Yampyrus Leach, Trans. Linn. Soc. London, XIII, p. 79. 
1878. Yampyrus Dobson, Catal. Chiropt. Brit. Mus., p. 469. 
Type-Species. — -Vespertilio spectrum Linnaeus. 
Geographic distribution. — Tropical America north to southern 
Mexico ; Greater Antilles. 
Number of forms. — Only the type species is recognized. 
Characters. — Dental formula (Plates I, II, fig. 3) : 
- 2 3. 1. - - 3 4 5 6 7 . 2- 2 1 - 1 2-2 3 - 3 
1 2 -. 1. - 2 3 4 5 6 7 * 2 - 2’ C 1 - 1’ pm 3-3’ ™ 3 - 3~ U ' 
Middle upper incisors low and wide, their cutting edges strongly 
oblique, but entire, and almost in contact with canines laterally; 
outer incisors pushed slightly forward out of tooth row, barely rising 
to. level of cingulum of canine. Canines relatively larger than in 
any other genus of Phyllostomidse, flattened in front, the moder- 
ately developed cingulum forming a low but distinct postero-internal 
cusp. Anterior premolar (pm*) with crown longer than wide, the 
height of its somewhat trenchant cusp barely equal to length of 
crown. Posterior premolar (pm 4 ) peculiar in the very slight indi- 
cation of the postero-external thickening. Upper molars with the 
same peculiarities as in C hrotopterus, but much exaggerated; dis- 
proportion between height of protocone and that of outer cusps 
very great, owing less to suppression of forming than to unusual 
elongation of latter; paracone and metacone so high that the outer 
side of the teeth presents a conspicuous oblique surface, about half 
of which is limited above by the sharply trenchant edge of the 
fourth commissure, which has practically no posterior thickening 
to represent metastyle. The three main cusps are so near together 
that the triangle indicated by their points is scarcely more than 
one-fourth the area of base of crown.® Parastyle and mesostyle 
® In Chrotopterus this triangle is about one-tliird of the crown area, while in 
Phyllostomus it is between one-third and one-half. 
