RHYNCHISCUS. BALANTIOPTERYX. 159 



Rhynchiscus naso (Wied), see Elliot, Check-List Mamm. N. Am. 

 Cont. and West Indies, 1905, No. 1181, p. 492. 



Rhynchiscus naso priscus G. M. Allen. 



Rhynchiscus naso priscus G. M. Allen, Proc. Biol. Soc. Wash., 

 XXVII, 1914, p. 109. 



Type locality. Xcopen, Quintana Roo, southern Mexico. 



Gent. Char. Similar to R. naso, but shorter forearm; smaller skull, 

 with a conspicuous cingulum cusp anteriorly and posteriorly on ante- 

 rior upper premolar. 



Color. Top and sides of head and upperparts of body mixed black 

 and mummy-brown, hairs tipped with white; these forming a broken 

 whitish band on lower back; underparts dull whitish, washed with 

 buffy on the belly, hairs slaty at their base; a patch of white at the 

 base of forearm internally; femora, tibiae, free portion of the tail and 

 proximal half of the interfemoral membrane amber-brown; on fore- 

 arm externally on border of proximal third is a rusty line, beyond 

 which are four small whitish and buff tufts. A small whitish tuft 

 at base of each ear. Type in Museum of Comparative Zoology, 

 Cambridge, Mass. 



Measurements. Forearm, 38.5. Skull: Greatest length, 12; 

 zygomatic width, 7.2; intertemporal width, 2.3; mastoid width, 

 6.5; length of upper tooth row, 4.6,- length of mandible, ; length 

 of lower tooth row, 4.8. Type in Museum of Comparative Zoology, 

 Cambridge, Mass. 



Genus Balantiopteryx. (168). 



Balantiopteryx io Thomas. 



Balantiopteryx io Thos., Ann. and Mag. Nat. Hist., 7th Ser., XIII, 

 1904, p. 252. 



Type locality. River Dolores, near Coban, Guatemala. Type 

 in British Museum. 



Gent. Char. Size very small; tragus slender, tip rounded; lobule 

 opposite base of inner margin, and another higher up. Wing-sacs in 

 center of membrane; wings attached to distal end of tibia; calcar 

 slender, not reaching the knee; base of interfemoral membrane hairy. 



Color. Above and beneath, and membranes, dark brown; no 

 white edgings to wings. 



Measurements. Total length, 52; tail, 12; ear, 12; tragus, 3; 

 thumb, 5.6; third finger, metacarpal, 31.5; fifth finger, metacarpal, 36; 

 tibia, 14; leg and foot, 22; calcar, 10.5. Skull: Greatest length, 12.3; 

 basal length, 8.7; zygomatic breadth, 8.8; across muzzle, 6; mastoid 

 breadth, 7.6; palatal length, 3.3. 



