THE FAMILIES AND GENERA OF BATS. 91 
Number of forms . — The type species is the only member of the 
genus now known. 
Characters. — Like Peropteryx , but rostrum so little inflated anteri- 
orly that its dorsal profile slopes conspicuously forward toward line 
of tooth row. Ears joined across forehead by "a band of membrane 
3 mm. high. In the only known species the wings are white from 
level of elbow outward (five specimens examined). 
Species examined.— Per onymus leucopterus (Peters). 
Remarks. — The peculiar form of the rostrum, together with the con- 
nected ears, seem enough to give Peronymus generic rank. Though 
in exactly the same position, the wing sac is better developed in the 
female of Peronymus than in that of Peropteryx. 
Genus CENTRONYCTERIS Gray. 
1838. Centronycteris Gray, Mag. Zool. and Bot., II, p. 499 (subgenus of 
Proboscidea ) . 
1867. Centronycteris Peters, Monatsber. k. preuss. Akad. Wissensch., Ber- 
lin, p. 478 (genus). 
1878. Centronycteris Dobson, Catal. Cbiropt. Brit. Mus., p,- 371 (subgenus 
of Saccopteryx) . 
Type-speeies. — V espertilio calcarata Wied=F. maximiliani Fischer 
{Saccopteryx wiedi Palmer). 
Geographic distribution. — Brazil and Peru. 
Number of forms. — The type is the only known species. 
Characters. — Similar to Saccopteryx , but whole animal, including 
skull, more slender. Lower edge of orbit so little expanded that 
tooth row is distinctly visible from above. Wing sac not known (all 
the specimens thus far taken have been females), but probably situ- 
ated near edge of antebrachial membrane close to shoulder. 
Species examined. — Centronycteris maximiliani (Fischer). 
Genus MYROPTERYX Miller. 
1906. Myropteryx Miller, Proc. Biol. Soc. Washington, XIX, p. 59, May 1, 
1906. 
Type-species. — Myropteryx pullus Miller. 
Geographic distribution. — Brazil and Dutch Guiana. 
Number of forms. — The type is the only member of the genus yet 
known. 
Characters. — Externally most nearly resembling Peropteryx , with 
which it agrees in position of wing sacs, but with broader head and 
more widely separated ears. Skull essentially like that of Saccop- 
teryx, , but with shorter, relatively deeper rostrum. Teeth differing 
from those of all the previously known sac-winged genera in the 
absence of hypocone in first and second upper molar, and in the 
minute, early deciduous upper incisor. 
Species examined. — Myropteryx pullus Miller. 
