A MONOGRAPH OF THE BATS OF NORTH AMERICA. 129 



Description. — Ears oval;* the anterior border of the ear sharply- 

 convex, inclining' backward and npward to the rounded tip; the upper 

 hall" of the ])0.sterior border is concave and without scallop. The lower 

 half is provided with a small, reverted scallop, which is continuous with 

 that of the space l)etween the external ridge and the nonrevolute 

 slightly tapering, external basal lobe; a delicate Hang extends from the 

 lobe to the angle of the mouth. 



Tlie fur is thicker on dorsum than on venter. It is Idack at the basal 

 two-thirds and dark gray verging to light ocher or almost white, at the 

 tips. It is lighter on the crown than elsewhere. On the venter the 

 same colors in-evail as on the dorsum, but the gray color is of a lighter 

 shade and tends to become white. The fur is unusually compact on 

 neck and below the lower jaw. 



In ISO. 54^00, U. S. N. M., the second digit is as long as the third meta- 

 carpal, i. e., the phalanx does not extend beyond the third metacarpal 

 phalangeal joint. The penis is slightly flattened and ends in a moder- 

 ately expanded prepuce. 



Membranes. — Intercostals three in number, the lowest appearing at 

 the knee and passing to the free margin of the endopatagium. Coraco 

 bracliialis lascicle appears at the middle of the humerus; it is simple and 

 apparently joins a vertical line which is extended downward from the 

 elbow. The triceps fascicle system with a single inferior line, but with 

 no superior obliques. Thefourth interspace with digital nerves as in Ves- 

 pertiUo, in this regard markedly differing from other examples of Ves- 

 perngo which have been examined. The interfemoral membrane is pro- 

 vided with a pubocalcaneal line. 



Mr. Dobson is inclined to believe that V. hesperiis is identical with 

 V. r.hraniKs, an old world species of extensive range being found in 

 middle Europe, the oriental region, and the northern part Of the Aus- 

 tralian region (see Appendix). But American zoologists have not 

 agreed with this opinion. Mr. F. W. True has made this question the 

 subject of a special note (Proc. of the U. S. iSTat. Mus., 1887, p. 515) and 

 concludes that V. hesperns is " distinct and valid." Mr. Dobson de- 

 scribes a specimen of Yespervgo from North America under the name 

 of V. merriami. This specimen I have not seen. Mr. True believes 

 that it is the same as the V. hesperns of the monograph. This is con- 

 clusive that Mr. Dobson after examining T'. hespcrus (as identified by 

 Mr. True) did not recognize it to be the same as V. abramus, but a dis- 

 tinct species. The material upon which the original description was 

 based was impertect. It consisted of two dry, imj^erfect skins and a 

 single alcoholic specimen. It has been obtained- since in abundance. 



Maxillary teeth. — Incisors both conical and unicuspid. The median 

 the larger. A small space between the lateral and the canine. Tlie 

 first premolar minute as in .l^«/a;j//a and wedged in between canine and 

 second premolar inside the longitudinal axis of the tooth row. The re- 



in the monograph, tbo statement ou page 41 thiit the ears are rounded is au error. 

 441— No. i;3 9 



