132 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
Species examined . — Phylloderma stenops Peters (type specimen of 
Guandira cayenensis Gray, of which the- skull is badly damaged). 
Remarks. — Although showing throughout a general resemblance to 
Phyliostomus this genus is readily distinguishable by the bifid middle 
upper incisors, the narrow lower molars, and the presence of the 
minute pm 3 . 
Genus TRACHOPS Gray. 
1825. Istiophorus Gray, Zool. Journ., II, p. 242, July, 1825 (part). Not of 
Lacepede, 1802. 
1846. Histiophorus Agassiz, Nomenclator Zool., Index Univ., p. 183. 
1847. Trachops Gray, Proc. Zool. Soc., London, p. 14. 
1865. Trachyops Peters, Monatsber. k. preuss. Akad. Wissensch., Berlin, p. 
512. 
1878. Trachyops Dobson, Catal. Chiropt. Brit. Mus., p. 481. 
Type-species. — Trachops fuliginosus Gray —Vampyrus cirrhosus 
Spix. 
Geographic distribution. — Tropical America, north to southern 
Mexico. 
Number of forms. — The type species is the only form now recog- 
nized. 
Characters. — Dental formula: 
-2 3. 1. - -34567.2-2 1-1 
1 2 -. T. - 2 3 4 5 6 7 * 2 - 2’ G - 1 - 1 pm 
2- 2 
3-3’ 
3-3 
m — =34. 
Maxillary teeth like those of Phyliostomus (anterior face of canine 
similarly grooved), but outer incisor very small, almost hidden 
between canine and inner incisor, cheek teeth relatively larger than 
in Phyliostomus , the greatest transverse diameter of m 2 nearly 
equal to width of palate ° ; m 1 and m 2 with large, well-defined 
hypocone and noticeably elongated postero-external segment. Ex- 
cept for the presence of a minute pm 3 smaller than the lower incisors 
and crowded completely from toothrow on inner side, so as to be 
invisible from without, the mandibular teeth differ from those of 
Phyliostomus in the noticeable compression or narrowing of the 
crowns of the molars, and the general elevation of all the cusps 
except the liypoconid of m 1 and m 2 , which is somewhat more reduced 
than in the related genus. The entoconid of these two teeth is, how- 
ever, much more developed than it is in Phyliostomus. Skull more 
elongated and rounded than that of Phyliostomus f interorbital 
region smoothly rounded and somewhat depressed; posterior zygo- 
matic expansion angular-emarginate in front, the anterior expan- 
sion barely indicated; audital bullae covering about half surface of 
cochleae, their height fully equal to width. Externally similar to 
a In Phyliostomus hastatus it is about one-half, in P. discolor considerably 
less than half, and in P. latifolius and P. longifolius slightly more than half. 
