56 
BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
Species examined. — Pterocyon biittikoferi (Jentink) P. dupreanus 
(Pollen) and P. Stramineus (Geoffroy). 
Remarks . — This genus is distinguishable from all other groups of 
Chiroptera by the structure of the audital bullae, and from its nearest 
ally, Rousettus , by the entire-edged lower incisors as well. 
The type specimen of Leiponyx biittikoferi , which I have examined 
in company with Doctor Jentink, appears to be unquestionably a 
Pterocyon in which the claw of the index finger is lacking. The 
individual is so old that the crowns of the molars are completely worn 
away, a fact that may have some bearing on the absence of the claws. 0 
While the form of the molars can not be determined, the incisors, 
canines, and anterior premolars agree perfectly with those of 
Pterocyon , as do also the general aspect of the. skull, the peculiar 
structure of the audital bullae, and, with the one exception already 
noted, the details of external form. 
Genus PTEROPUS Brisson. 
1762. Pteropus Brisson, Regn. Anim. in Classes IX distrib., 2 ed., p. TL3 
{vampyrus) . 
1799. Spectrum Lacepede, Tabl. des Div. Sousdiv. Orders et Genres, des 
Mammif., p. 15 {vampyrus). 
1866. Eunycteris Gray, Proc. Zool. Soc. London, p. 64 ( phaiops ). 
1870. Pselaphon Gray, Catal. Monkeys, Lemurs and Fruit-eating Bats Brit. 
Mus., p. 110 (ursinus=pselaphon) . 
1878. Pteropus Dobson, Catal. Chiropt. Brit. Mus., p. 15 (part, included 
Acerodon and Styloctenium) . 
1899. Pteropus Matschie, Flederm. des Berliner Mus. fiir Naturk., p. 5 
(part, included Pteralopex and Acerodon). 
1899. Sericonycteris Matschie, Flederm. des Berliner Mus. fiir Naturk., p. 30 
(subgenus of Pteropus containing the species rubricollis, temmincki, 
petersi, personatus, capistratus, molossinus, woodfordi) . 
1899. Eunycteris Matschie, Flederm. des Berliner Mus. fiir Naturk., p. 11 
(subgenus of Pteropus containing the species melanopogon, papua- 
nus, degener, neohibernicus) . 
1899. Spectrum Matschie, Flederm. des Berliner Mus. fiir Naturk., p. 19 (sub- 
genus of Pteropus containing the species poliocephalus, leucopteruSf 
pselaphon, vetulus, vampyrus, anetianus, rayneri, samoensis, dasy- 
mallus, loochooensis, formosus, rodricensis, lombocensis, brunneus . 
scapulatus, livingstoni, macrotis, epularis, assamensis, hypomela- 
nus, mariannus. 
Type- species. — V espertilio vampyrus Linnaeus. 
Geographic distribution . — From the Comoro Islands, Madagascar, 
and India, to Tasmania, Samoa, the Ladrones, and southern Japan 
(Kiusiu). 
o Specimens with one or both claws very imperfectly developed, or perhaps 
reduced by disease or injury, have been observed in Pteropus capistratus (No. 
122124, U.S.N.M. ) , P. hypomelanus (No. 105440), P. modiglianii (No. 140992), 
P. poliocephalus (No. 13594), and Acerodon sp. (No. 105454). 
