150 BULLETIN 5 7, 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 w T ell 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 space 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 Y and VI.) 
Tongue normal. Postrum 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- 
rionina; by Harrison Allen, who removed Brachyphylla and asso- 
ciated it with Phyllonycteris / and by Pehn, 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. 
9—9 
Molars^—; upper incisors situated beneath edge of nares. 
2-2 
3-3 
Centurio, p. 168. 
Molars 2 — ; upper incisors separated from nares by distinct horizontal area. 
3—3 
Anterior margin of orbit with a low but distinct bead ; interptery- 
goid space practically absent, the hamular processes almost per- 
pendicular to sagittal plane; choame 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 Sphceronycteris, p. 170. 
