150 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 



Geographic distribution. — Warmer parts of America north to Cuba, 

 southern Florida, and central Mexico. 



Characters. — Teeth highly abnormal. Upper molars with crowns 

 elongated across main axis of toothrow (very broad and short). 

 Paracone and usually the metacone also well developed at extreme 

 outer margin of tooth, the two cusps together with their commissure 

 forming a cutting edge, which is often rimmed by two cingula, an 

 outer and an inner. Protocone at extreme inner margin, except when 

 its place is taken by the shelf -like, often very large hypocone, which 

 in extreme instances resembles a second protocone. The srjace be- 

 tween the inner and outer cusps is occupied by a wide, slightly con- 

 cave crushing surface, the enamel of which is variously wrinkled and 

 roughened, rarely almost smooth. Lower molars with main portion 

 of crown nearly flat, its surface roughened as in the maxillary teeth. 

 On the outer edge are two low, broad cusps (the second occasionally 

 obsolete), the protoconid and hypoconid, between which a small 

 third, possibly the mesostyle, is sometimes present. On the inner edge 

 a conspicuous spike-like cusp arises opposite or slightly behind the 

 protoconid and a less conspicuous cusp occupies the posterior inner 

 angle of the crown. The larger of these cusps is the metaconid, as a 

 rudimentary elevation representing the last trace of the paraconid is 

 occasionally present in front of it (Artibeus). (Plates V and VI.) 

 Tongue normal. Eostrum usually though not invariably much 

 broadened and shortened. Antorbital canal indistinct, opening ante- 

 riorly by two or three minute orifices. Noseleaf usually present, 

 though sometimes rudimentary or absent. 



History. — This subfamily has been recognized as a distinct group 

 since 1855. It was subdivided by Gray, who separated the Centu- 

 lionina; by Harrison Allen, who removed Brachyphylla and asso- 

 ciated it with Phyllonycteris ; and by Eehn, who again regarded the 

 Centurioninse as distinct. The group as a whole appears to me very 

 homogeneous, and I can see no reason to remove any of its genera. 



Principal subdivisions. — Nineteen genera of Stenoderminae are now 

 known. 



KEY TO THE GENERA OF STENODERMIN^E. 



Rostrum much shortened, considerably less than half as long as braincase. 



2—2 

 Molars—-; upper incisors situated beneath edge of nares. 



„ „ Genturio, p. 168. 



Molars _; upper incisors separated from nares by distinct horizontal area. 



Anterior margin of orbit with a low but distinct bead ; interptery- 

 goid space practically absent, the hamular processes almost per- 

 pendicular to sagittal plane; choanoe forming a nearly circular 

 backward-directed opening Ametrida, p. 171. 



Anterior margin of orbit produced into a conspicuous plate ; inter- 

 pterygoid space evident, the hamular processes directed backward 

 and slightly outward ; choanse normal Sphwronycteris, p, 170. 



