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. — Antrosous pattidus (Le Conte) , A. pacificus 

 (Merriam), and A. minor Miller. 



Remarks. — Among the American A^espertilionidoe 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 Antrosous is more primi- 

 tive than Nyctophilus: The opposite is, however, true of the reduced 

 number of lower incisors, the shortened protocone of to * and m * and 

 the peculiar deepening of the anterior part of the skull. 



Genus NYCTOPHILUS Leach. 



1813. Plecotus Geoffroy, Descr. de 1'lSgypte, II, p. 112 (part). 



1822. Nyctopliilus Leach, Trans. Linn. Soc. London, XIII, p. 78. 



1831. Barbastellvs Gray, Zoological Miscellany, p. 38. Not Barbastella 



Gray, 1821. 

 1878. Nyctophilus Dobson, Oatal. Chiropt. Brit. Mus., p. 171. 



Type-species. — Nyctophilias geoffroyi Leach =Plecotus timoriensis 

 Geoffroy. 



Geographic distribution. — From Timor to the Fiji Islands and 

 Tasmania. 



Number of forms. — Three species of Nyctophilia are currently 

 recognized. 



Characters. — Dental formula : 



-2 -A, -- -4 5 6 7, 1-1 „ 1-1 _ 1-1 m 3-3 =30 _ 



12 3. 1. -2-45 6 7 3-3' \-V r 2-2' 3^3~ 



Except for the presence of the full number of lower incisors the 

 teeth do not differ very noticeably from those of Antrosous. 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 - 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 x or to 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 



