236 BULLETIN 57, UNITED STATES NATIONAL MUSEUM. 
more than half as long as braincase, without distinct lateral ridges; 
no trace of basisphenoid pits; audital bullae large but not peculiar 
in, form, covering nearly the entire cochleae, their diameater equal to 
nearly twice the distance between them. Ears separate but large, 
extending considerably beyond tip of muzzle when laid forward; 
tragus long and slender, straight. Muzzle squarely truncate, with 
low but distinct horseshoe-shaped ridge above nostrils ; behind this a 
large flattish swelling on each side. Metacarpals of third and fourth 
fingers equal. 
Species examined. — Antrozous pallidus (Le Conte), A. pacificus 
(Merriam), and A. minor Miller. 
Remarks . — Among the American Vespertilionidoe this genus is at 
once recognizable by the form of the muzzle. The known species are 
all of large size for the group ; and their color is a characteristic pallid 
tawny. 
In the slight development of the nose leaf Antrozous is more primi- 
tive than Nyctophilus. The opposite is, however, true of the reduced 
number of lower incisors, the shortened protocone of m 1 and m 2 and 
the peculiar deepening of the anterior part of the skull. 
Genus NYCTOPHILUS Leach. 
1813. Plecotus Geoffroy, Descr. de 1’Egypte, II, p. 112 (part). 
1822. Nyctophilus Leach, Trans. Linn. Soc. London, XIII, p. 78. 
1831. Barhastellus Gray, Zoological Miscellany, p. 38. Not Barhastella 
Gray, 1821. 
1878. Nyctophilus Dobson, Catal. Chiropt. Brit. Mus., p. 171. 
Type-species. — Nyctophilus geoffroyi Leach = Plecotus timoriensis 
Geoffroy. 
Geographic distribution.- — From Timor to the Fiji Islands and 
Tasmania. 
Number of forms. — Three species of Nyctophilus are currently 
recognized. 
Characters. — Dental formula : 
- 2 -. 1 . 45 6 7 „. 1-1 „ 1-1 _ 1-1 
12 3 . 1 . - 2 - 4567 * 3 - 3 ’* 2 - 2 ’ 
m 
Except for the presence of the full number of lower incisors the 
teeth do not differ very noticeably from those of Antrozous. Lower 
incisors with the crowns of the usual low, long, trifid form, not high 
and narrow as in the related genus; upper incisor scarcely half as 
high as canine. Cheek teeth strictly normal, m 1 and m 2 with the 
protocone large, its base extending backward to line of metacone; 
neither tooth shows any distinct trace of hypocone ; m 3 with rather 
more than half the crown area of m 1 or m 2 , its metacone and meso- 
style together with the commissures present though small; lower 
molars with the discrepancy in height between inner and outer cusps 
