THE FAMILIES AND GENERA OP BATS. 255 



row between canines; crowns deeply and unequally bifid, the outer 

 lobe less than half as large as inner; height about equal to that of 

 large cingulum of canine; no indication of backward prolongation 

 of crowns. Canines relatively low and weak, the height of the upper 

 teeth distinctly lets than the distance between their bases, the diameter 

 of the shaft in both maxillary and mandibular teeth much less rela- 

 tively to that of crown than in Nyctlnomus; anterior surface with 

 longitudinal groove well developed, especially in upper teeth, and 

 anterior cutting edge unusually prominent ; cingulum well developed, 

 forming a distinct posterior cusp above, and anterior and posterior 

 cusp below. Anterior upper premolar (pm s ) a minute (sometimes 

 deciduous) spicule considerably smaller than cingulum of canine. 

 Posterior upper premolar (pm*) essentially as in Nyctinomvs, but 

 main cusp smaller and lower, and postero-internaj heel more devel- 

 oped ; antero-internal cusp well developed but small. Lower pre- 

 molars proportioned as in Nyctinomus but resembling the canine in 

 the much reduced diameter of the cusp as compared with the crown. 

 This is especially noticeable when teeth are viewed from above, the 

 periphery of the crowns appearing like an enormously developed cin- 

 gulum. Molars essentially normal, but differing from those of Nyc- 

 tinomus in several important particulars. In all of the upper teeth 

 the protocone is unusually narrow and ridge-like, leaving a very wide 

 concave area between bases of cusps; hypocone barely indicated by a 

 slight angularity of posterior commissure of protocone ; m b with 

 crown area fully three-fourths that of m 1 and much, more than that 

 of pm % the metacone and third commissure well developed. Lower 

 molars peculiar in the very narrow triangles and strongly incurved 

 main cusps. As in the upper teeth, the concavities of the crowns are 

 unusually large as compared with the diameter of the cusps. Proto- 

 conid of to , and m 3 with a distinct incipient secondary cusp on outer 

 side slightly above middle. Inner cusps as in Nyctinomus, the ento- 

 conid of m 3 equally well developed. Skull broad and much flattened, 

 in general appearance not unlike that of Tylonycteris, the dorsal pro- 

 file straight from nares to lambda ; depth of braincase about one-third 

 greatest breadth, its length about one and one-third times that of ros- 

 trum ; depth of rostrum in lachrymal region slightly less than one-half 

 lachrymal breadth and about one-half length of rostrum. Lachrymal 

 ridges prominent, giving the rostrum a peculiar diamond-shaped out- 

 line. Antorbital foramen large, opening conspicuously forward. Palate 

 broad, slightly arched, both laterally and longitudinally, the anterior 

 emargination about twice as long as wide, extending back to middle 

 of canine. Basisphenoid pits barely indicated. Pterygoids parallel. 

 Audital bullae about as in Nyctinomus, but slightly more emarginate 

 on inner side. Zygoma weak, not expanded at middle. Mandible 

 with coronoid process slender, high, and strongly curved backward, 



