248 



BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



lower canines in contact with each other or separated by a narrow 

 .space. Upper premolar large, its crown area slightly more than half 

 that of first molar, its antero-internal cusp well developed. Lower 

 premolars closely crowded, the anterior much smaller than posterior, 

 the crowns of both teeth wider than long, and slightly crescentic in 

 outline. Molars strictly normal, m 1 and m z with hypocone obsolete 

 though obviously indicated, m 3 with second commissure always well 

 developed, and a small third commissure sometimes present; m t 

 and m 2 with low protoconid and large, long entoconid, m 3 with 

 protoconid obsolete, and entoconid smaller than hypoconid. Skull 

 (figs. 39 and 40) broad and flattened, the rostral portion marked 



by conspicuous lachrymal 

 ridges, but sagittal crest 

 obsolete; lachrymal 

 breadth distinctly greater 

 than length of rostrum, 

 which in turn is about two- 

 thirds that of brain case; 

 depth of rostrum dis- 

 tinctly less than that of 

 brain case; antorbital fo- 

 ramina opening very con- 

 spicuously forward at bot- 

 tom of groove formed be- 

 tween side of rostrum and 

 high lachrymal ridge ; pal- 

 ate distinctly arched, and 

 slightly domed, its ante- 

 rior portion entire or with 

 two minute foramina; ba- 

 sisphenoid pits obsolete or 

 absent; audital bullae 

 strongly emarginate on inner side as usual in the family. External 

 form thickset and heavy, much like that of Eomops. Ear short 

 orbicular, extending somewhat more than halfway from eye to nostril 

 when laid forward; keel low but distinct; tragus small, narrowed 

 above ; antitragus well developed, but not thickened ; anterior termi- 

 nation of ear on forehead close to that of opposite side. Lips much 

 thickened, but not specially expanded or wrinkled, the upper lip 

 sprinkled with spoon hairs, particularly in front. Muzzle pad indis- 

 tinct, without definite ridges. Legs, feet, and tail thick and heavy. 

 Membranes leathery. 



Species examined.— Molossops cerastes (Thomas), M. paranus 

 Thomas, M. planirostris Peters, M. temmincMi (Burmeister) . 

 Remarks.— Both externally and in the structure of the skull this 



Fig. 39.— Mot.ossops planirostris. Paraguay. 

 No. 37741. X 2. 



