282 PROCEEDINGS OP THE ACADEMY OP 



base ; apical third brownish-grey at neck, lighter at pubis ; teeth as 8223, 

 also ear and membranes ; joints of tail ten ; in both feet and thumb large, but 

 specimens young. 



Measurements. 



Length of head V" Length of foot 4'" 



" " body l r/ Heigh th of auricle 5 /// 

 " " tail \"-Z'" " " tragus ?>\" f 



" " humerus l // -4 /// Length of '2d joint index finger J. f " 



" " thumb 3/" Expanse 8 // -2 /// 



Two young individuals, % . Nos. 8222, 8223, Mus. of Smithsonian Insti- 

 tution. Alcohol. 



Lower California. John Xantus. 



Also young individual mentioned in Mon. '(hoc. c ;t.) as a variety of V. 

 nitidus {V. Oregonensis). It very closely resembles sp. 8222. Dry. No locality. 



/3. Interfemoral membrane relatively large ; each joint of tail a third longer than 

 each of ; terminal joint not exserted, (a small tip of cartilage may be exserted ;) 

 color of membranes and ear light brown, excepting V. exilus. 



V. agilis, n. s. " 



Fur silky, above of a very dark plumbeous verging to black, with apical 

 fourth of a decided dark brown ; on back, running to a lighter shade on head, 

 where the fur has a more woolly texture. Fur wanting from region of loin 

 and interfemoral membrane. Beneath, the base of the fur the same as above, 

 apical fourth being of a lighter brownish grey ; basal third posterior sur- 

 face of auricles being clothed with a few sparse unicolored greyish hairs. 

 Auricle almost bluntish at tip, internal basal lobe sharply pointed ; tragus 

 acuminate, broad at basal third ; external basal lobe prominent, free, broadly 

 crescentic ; joints of tail nine, enclosed in interfemoral membrane ; nostrils 

 mutilated, oblique, probably palmate. 



Measurements. 

 Length of head V" Length of foot 3'" 



body I" " auricle V" 



tail V-&" " tragus Z\" f 



humerus l"-4'" " 2d joint index finger \'" 



thumb 2\"' Expanse 9" 



One individual 9. No. ? Mus. of Smithsonian Institution. Alcohol. 

 Dr. Sartorius. Mirador, Mexico. 



V. volans, n. s. 



Fur: above dark plumbeous at basal third; apical third obscure, light 

 brown, scarcely any extension on membranes; basal third interfemoral mem- 

 brane same. Below, basal two-thirds plumbeous, shade lighter than above ; 

 apical third a light-brownish fawn. Moderate extension of hairs upon mem- 

 branes to near elbow, and upon basal third interfemoral membrane. Auricle 

 slightly "scooped out;" external basal lobe salient, quadrate; tragal lobe 

 very salient ; nostrils elliptical ; index finger strong, membrane uniting it with 

 middle finder, ample ; joints of tail nine ; tip barely exserted ; excalcaneal 

 lobe conspicuous ; upper incisors as usual; lower external scarcely if at all 

 quadrilobed; first and second upper premolars placed a little within line ot 

 arch. Skull: upper border anterior nares semicircular; facial bones abbre- 

 viated, causing the brain case to appear greatly inflated. 



Measurements. 

 Length of head V" Length of foot 2\" f 



" body V r Height of auricle 5 7// 



" tail \ ff -<b ,ff " tragus 3 /// 



" humerus l"-5'" Length of 2d joint index finger V" 



" thumb Z /f/ Expanse 9 // 



[Aug. 



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