122 PROCEEDINGS OF THE NATIONAL MUSEUM vol. uo 



Genus Euderma H. Allen 



Histiotus J. A. Allen, 1891, p. 195. (Part.) 

 Euderma H. Allen, 1892, p. 467. 



Type species: Histiotus maculatus J. A. Allen. 



Distribution: Southwestern United States and probably north- 

 western Mexico. 



Description: Supraorbital region sharply ridged (fig. 4); temporal 

 ridges not coalescing posteriorly to form a sagittal crest; brain case 

 exceptionally elongated; zygoma relatively heavy, with postorbital 

 expansion in middle third of arch; median postpalatal process a bifid 

 prominence; auditory bulla roughly elliptical in outline; presternum 

 longer than wide. 



Upper incisors in line with tooth row; I^ simple, without accessory 

 cusps (fig. 2), except occasionally near cingulum, and small, only 

 slightly larger than I^; I^ close to or touching upper canine; P^ minute; 

 hypocone cusp barely indicated on M* and M^; third commissure 

 longer than second and metacone relatively well developed in M^; 

 lower canine reduced in thickness, not exceeding P4 in height, and 

 possessing a prominent anterointernal secondary cusp almost equaling 

 primary cusp in height; Pi about one-half the size of P4, and not 

 crowded; P3 absent; P4 single-rooted and possessing a well defined 

 metaconid cusp. 



No large glandular masses on muzzle (fig. 7); nostril opening 

 small, of primitive vespertilionid type (fig. 8), provided with a cornu, 

 and not extended posteriorly or opening upward; auricle and tragus 

 very large (fig. 9) ; tragus not provided with a basal lobe, but united 

 with posterior basal lobe of auricle; anterior basal lobe of auricle 

 complete; transverse ribs on auricle extend to posterior border of 

 auricle; second phalanx of third digit longer than first phalanx (fig. 6) ; 

 calcar not keeled; interfemoral membrane attached to base of last 

 caudal vertebra; coloration black and white in bold pattern; mem- 

 branes and ears grajash. 



Euderma niaculatuni J. A. Allen 



Histiotus maculatus J. A. Allen, 1891, p. 195. 

 Euderma maculata H. Allen, 1894, p. 61. 



Holotype: AMNH 3920/2991; young adult skin (skull lost sub- 

 sequent to original description); "caught on a fence" in March 1890, 

 by Thomas Shooter; near Piru, Ventura County, Calif, [probably 

 mouth of Castac Creek, Santa Clara Valley, 8 miles east of Piru, 

 Los Angeles County, Calif. (Miller, 1897, p. 49)]. 



Distribution: Southwestern United States and probably north- 

 western Mexico (fig. 10). West to Washoe County, Nev.; Mariposa, 



