THE FAMILIES AND GENERA OF BATS. 203 



mass (in females 10 mm. long and 3 mm. wide) near middle of fore- 

 arm. Skull (fig. 31) and teeth as in Myotis, but cingulum.of lower 

 canine forming a small cusp anteriorly and inner cusps of lower 

 molars unusually well developed. 



Species examined. — Pizonyx vi/'esi (Menegaux). 



Remarks.— The size of the foot relatively to the tibia exceeds that 

 in any of the large- footed species of Myotis, while the extreme com- 

 pression of the claws is noticeably unlike any members of the related 

 genus. The presence of the glandular masses in the wing is a char- 

 acter unique in the family, though apparently analogous structures 

 occur on the ear of Rhogeessa gmcilis. 



Genus LASIONYCTERIS Peters. v 



1831. Yexpertilio Le Conte, MeMurtrie's Cuvier, Anim. Kingd., I, p. 31 

 (part). Not Tespertilio Linnseus 175,8. 



1864. Scotopliilux H. Allen, Monogr. Bats X. Amer., p. 27, June, 1804 

 (part). 



1865. Laxionyctrrix Peters, Mnnatsber. k. preuss. Akad. Wissensch., Ber- 

 lin, p. 648. 



1870. CneplialophUus Pitzingek, Sitzungsber. kais. Akad. Wissensch., Wien, 



Matb.-Naturwissensch. Classe LXII, p. 8 (part). 

 1875. Texprrhlcx Coues, in Cones and Yarrow, Zoology of Wheeler's Exped., 



p. 83. 

 1878. Lasionycterix Dobson, Catal. Chiropt. Brit. Mus., p. 238 (subgenus of 



Yexprrugo). 

 1894. Laxionycterix H. Allen, Monogr. Bats X. Amer., 1893, p. 104, March 



14, 1894. 

 1897. Laxionyctrrix Millek, North Amer. Fauna, No. 13, p. 85, October 16, 



1897. 



Type-species. — Vespertilio iwctivagans Le. Conte. 

 Geographic distribution. — Northern North America south through 

 the United States. 

 Number of forms. — The type species only. 

 Characters. — Dental formula : 



-23.1.-2-4 5 6 7 .2-2 1-1 2-2 3-3 oa 



123.1.-2 3 45 6 7 * 3^3' ° 3TT' P m 3^3' W 3^3 ~ 36 - 



Structure of teeth as in Myotis; upper incisors of same general 

 form and relative size, the inner strongly bicuspidate, the outer sim- 

 ple ; cheek teeth not peculiar except that pm 3 is absent, and the hypo- 

 cone is distinctly indicated in first and second upper molars; third 

 upper molar with more than half the crown area of first, its metacone 

 nearly as large as parac'one, and the three commissures well developed. 

 Skull flattened, with broad rostrum, the depth of braincase including 

 audital bullae about three- fourths mastoid breadth ; sagittal crest obso- 

 lete; interorbital region wide, flattish, the upper edge of orbit with 

 a low " bead," which near middle forms an angle suggesting an 



