THE FAMILIES AND GENERA OF BATS. 235 



philus being supposed to have strictly Vespertilionine relationships, 

 while Antrozous appeared to be derived from some primitive Phyl- 

 lostomine stock. While the genera are very distinct, I am inclined 

 to accept Peters's view and place them together as a subfamily of 

 Vespertilionidae. In any event, Nyctophilus seems to be not specially 

 allied to the Plecontines, as its muzzle is very differently formed, and 

 the teeth show no tendency to become reduced in strength. 



Principal subdivisions. — Two genera of Nyctophilia? are now 

 known, one peculiar to each of the regions inhabited by the group. 



KEY TO THE GENERA OF NYCTOPHILINjE. 



Lower incisors 2-2 ; extremity of muzzle with distinct horseshoe-shaped 

 ridge Antrozous, p. 235. 



Lower incisors 3-3; extremity of muzzle with low but evident nose- 

 leaf Nyctophilus, p. 236. 



Genus ANTROZOUS H.Allen. 



1862. Antrozous H. Allen, Proc. Acad. Nat. Sci. Philadelphia, p. 247. 



1878. Antrozous Dobson, Catal. Chiropt Brit. Musi, p. 170. 



1894. Antrozous H. Allen, Monogr. Bats N. Amer. (1893), p. 64, March 14, 



1894. 

 1897. Antrozous Miller, North American Fauna, No. 13, p. 42, October 16, 



1897. 



Type-species. — Vespertilio pdllidus Le Conte. 



Geographic distribution. — "Warmer parts of western North Amer- 

 ica, from Texas to the Pacific coast, and from the Columbia River to 

 central Mexico. 



Number of forms. — Three forms of Antrozous are now recognized. 



Characters. — Dental formula : 



-2-.-1. 4567.1-1,1-1 1-1 3-3 oa 



12-. -1. -2-45 67*2-2' 1-1' ' 2-2' 3^3" 



Upper incisor large, simple, its shaft more than half as high as 

 canine, against which the tooth is crowded at base ; lower incisors sub- 

 equal, trilobed, the high, narrow crowns very strongly imbricated. 

 Canines moderately large, not peculiar in form, the cingulum distinct 

 but small. Cheek teeth normal both above and below ; m 1 and m 2 

 without hypocone, and with base of protocone so short that it does not 

 extend back to level of metacone, the W pattern rather shallow but 

 perfectly distinct, m s with less than half the crown area of m 1 or m 2 > 

 its protocone, paracone, and parastyle well developed, but no other 

 cusps present, and the second commissure reduced to the merest trace ; 

 lower molars with outer cusps unusually high as compared with those 

 of inner side ; m 3 with second triangle much reduced, and apparently 

 consisting of the hypoconid only. Skull with rather high, smooth 

 braincase, deep interorbital region, and large rostrum, the dorsal 

 profile with no special concavities or convexities; rostrum decidedly 



