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. Glyphonycteris Thomas, Ann. and JIag. Nat. Hist., 6th ser., XVIII, p. 



301, October, 1896. 

 1906. Glyphonycteris Andeesen. Ann. and Mag. Nat. Hist., 7th ser., XVIII, 



p. 58, July, 1906. 



Type-species. — Glyphonycteris sylvestris Thomas. 



Geographic distribution. — Costa Rica, 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. — Glyphonycteris 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. 



