238 BULLETIN Si, UNITED STATES NATIONAL MUSEUM. 



Genus TOMOPEAS Miller. 



1900. Tomopeas Miller, Ann. and Mag. Nat. Hist., 7th ser., VI, p. 570, 

 December, 1900. 



Type-species. — Tomopeas ravus Miller. 



Geographic distribution. — Peru. 



Number of forms. — Only the type species is thus far known. 



Characters. — Dental formula : 



-2-. 1. 45 6 7 .1-1 1-1 1-1 3-3 



12 -. 1. - 2 - 4 5 6 7* 2=2' C 1=1 '^2=2' 3-8 



Upper incisor close to canine though not actually in contact its 

 shaft subterete, nearly half as high as that of canine, strongly 

 curved backward at extremity, the posterior surface slightly concave ; 

 cingulum forming a small but distinct inner basal cusp. Lower 

 incisors subequal, trifid, slightly imbricated. Canines well devel- 

 oped, but showing no special peculiarities in form; shaft of upper 

 canine slightly curved backward; cingulum of lower canine forming 

 distinct anterior basal lobe. Upper premolar (pm 4 ) relatively large, 

 its crown area more than three : fourths that of first molar, very 

 slightly emarginate posteriorly, its inner cusp well developed. Lower 

 premolars slender, not peculiar in form. Molars normal ; m 1 and m - 

 with large protocone, the commissure of which joins the very dis- 

 tinct hypocone^ inner border of tooth with noticeable concavity just 

 in front of hypocone ; m " about as large as premolar, its metacone 

 and three commissures well developed. Lower molars with all the 

 cusps present, their development normal, except that the paraconid 

 is unusually low. Skull with smoothly rounded, somewhat flat- 

 tened braincase, the occipital depth about two-thirds breadth above 

 posterior roots of zygomata. Rostrum considerably more than half 

 as long as braincase, flattened above, with distinct median groove and 

 a shallow though noticeable longitudinal concavity on each side. No 

 sagittal crest, but edges of orbits distinctly ridged. Outline of nares 

 forming rather more than half of a circle when viewed from above. 

 Palate slightly concave longitudinally, distinctly concave laterally, 

 its anterior emargination shallow, with distinct median projection, 

 its posterior prolongation scarcely extending beyond molars. Ptery- 

 goids parallel, inclosing a nearly square space; hamulars minute, 

 slightly bent inward. Audital bullae large, their diameter noticeably 

 exceeding space between them, but greatly emarginated on inner 

 side and so flattened that they are almost discoid, the edge curving 

 over postero-internally, but not elsewhere. No basisphenoid pits, 

 Externally not unlike a small Pipistrellus, but upper lips very 

 widely spreading, ear with no anterior basal lobe, but with a rudi- 

 mentary keel ; tragus short and blunt ; antitragus small but distinct. 



