THE FAMILIES AND GENERA OF BATS. 
125 
Characters. — Externally similar to Micronycteris , but with con- 
necting band of ears very low. Skull and teeth as in Micronycteris , 
except that the incisors both above and below are notably peculiar. 
Inner upper incisor subtereti-conical, the crown slightly wider than 
long at base, the shaft convex in front, concave behind, tapering to a 
simple, moderately acute point. The two teeth are set very obliquely, 
their bases wide apart, their shafts in contact just below tip. Cingu- 
lum very slightly developed, so that distinction between crown 
and root is made less evident than in Micronycteris. Outer incisor 
small, much as in Micronycteris , but somewhat overlapping base of 
inner tooth. Lower incisors much crowded between canines, the pos- 
terior outline of the row convex, the anterior margin slightly con- 
cave. The outer tooth is tightly wedged into angle between inner 
and canine, which are strongly in contact; crowns of both teeth, but 
especially of inner, much wider than long. Otherwise they resemble 
the lower incisors of Micronycteris. 
Species examined. — Xenoctenes hirsutus (Peters). 
Remarks.- — While the upper incisors in this genus are less modified 
than those of Micronycteris , the lower incisors are distinctly more 
specialized in form. 
Genus GLYPHONYCTERIS Thomas. 
1896. Gly phony cter is Thomas, Ann. and Mag. Nat. Hist., 6th ser., XVIII, p. 
301, October, 1896. 
1906. Glyphonycteris Andersen, Ann. and Mag. Nat. Hist., 7th ser., XVIII, 
p. 58, July, 1906. 
Type-species. — Gly phony cteris sylvestris Thomas. 
Geographic distribution. — Costa Pica, Peru, Guiana, and Brazil. 
Number of forms . — Three species are known. 
Characters.- — Like Micronycteris , but ears separate; skull with ant- 
orbital region distinctly inflated, and basisphenoid pits deep and 
distinct, with sharp median dividing ridge; middle upper incisor 
with anterior face flat; upper premolars with main cusp situated 
distinctly in front of middle of crown, the point slender and slightly 
recurved, neither tooth with evident indication of rudimentary 
styles; the two teeth not differing conspicuously from each other in 
form, the inner border with well developed secondary cusp separated 
from main cusp by deep longitudinal groove ; concave areas of 
molars larger proportionally to the cusps than in Micronycteris / 
lower incisors trifid, the division indicated nearly to base of crown 
by grooves along anterior face. 
Species examined —Gly phony cteris sylvestris Thomas, G. behni 
Peters, and G. brachyotis Dobson. 
Remarks. — This genus, though closely related to Micronycteris and 
Xenoctenes , is sufficiently characterized by the form of the upper pre- 
molars and the inflated antorbital portion of the skull. 
