170 TBSPEETILIONIB^E. 



i". Nostrils simple, scarcely project- 



3 3 



ing ; premolars 3:33. 

 i'". Nasal apertures crescentic; first 



and second upper premolars 



much smaller than the third 12. Vespeetilio, p. 284. 

 f. Nasal apertures circular ; first 



and second upper premolars 



nearly equal to the third. ... 13. Kehivoula, p. 330. 



B. Grown of the head greatly elevated 

 above the face-line ; upper incisors 

 separated from the canines, and also 

 in front Gh-oup III. MINIOPTERI. 



a. Premolars 3^. 



a'. Base of thumbs and soles of feet 



simple 14. Natalus, p. 341. 



h'. Base of thumbs and soles of feet 



with adhesive disks 15. Thyeoptera, p. 345. 



b. Premolars j^g 16. Miniopterus, p. 347. 



1. ANTROZOUS. 



Antrozous, Allen, Proc. Philad. Acad. Nat. Sci. 1862, p. 247 ; Monogr. 

 Bats N. America, 1864, p. 66, 



Muzzle cylindrical, margins of the nasal apertures continuous with 

 the rim of a small disk terminating the muzzle above ; ears sepa- 

 rate, tragus long, attenuated upwards ; crown of the head very 

 slightly elevated above the face-line ; tail contained in and produced 

 to the hinder margin of the interfemoral membrane, no postcalcaneal 

 lobe. 



Incisors i^, the upper incisors close to the canines ; premolars 



i^, the single upper premolar large, close to the canine ; the first 

 lower premolar small, crushed in between the canine and second 

 premolar. 



Range. Nearctic Region (Califomian and Rocky Mountain sub- 

 regions). 



This genus is represented by a single species of very peculiar 

 physiognomy, resembling, in the form of the muzzle, the Bats of the 

 genus Megaderma, and differing from all other species of Vesperti- 

 lionidce in having four lower incisors only. The skeleton, however, 

 is very similar to that of the species of Nyctojphilus and Scotophihis, 

 and differs only in the greater development of the fibula. The skull 

 rather resembles that of Scotophilus, but the facial bones are much 

 more prolonged beyond the infraorbital foramen ; as in Scotophilus, 

 the supraoccipital crest is the highest point of the skull ; the bony 

 palate extends to the middle of the zygomata ; the tympanic bullae 

 are large, but leave a small portion of the cochleae uncovered ; the 

 hasioccipital is rather wide between the cochleae, and is not marked 

 by any excavations (Plate XI. fig. 6a). 



