NATURAL SCIENCES OF PHILADELPHIA. 247 



Fur not so extensive as in other species of the genus. Posteriorly extend- 

 ing on to the wing membrane from body, as in L. cinereus, running down 

 the interfemoral membrane two-thirds the distance and on to the foot ; a very 

 small brownish tuft is seen at base of thumb, and on the membrane at and 

 above the elbow, while the fourth and fifth fingers are naked. Anteriorly the 

 hair spreads up under the arm to wrist as in other species, bnt less 

 thickly. It also runs down a little way upon the interfemoral and is obser- 

 vable upon the membrane between the ulna and humeris. The wing mem- 

 brane extends to base of toes. The calcaneum is moderately developed. 



General hue olive brown. Blackish at base, dirty brown at centre, with 

 a clearer tip. The color is somewhat darker behind than in front. 



4 12 14 

 Dentition, m -, c-, in. -, c-, m -=30. 



5 1 6 15 



The small premolar placed behind the canine of the upper jaw of L. 

 cinereus and novaboracensis is here absent. 



This species in size, physiognomy, number of incisors, and character of the 

 distribution of the fur resembles the type of Lasiurus, while in shape of the 

 ears and disposition of molars it is akin to Scotophilus. The interfemoral 

 membrane is scarcely more hairy than in S. noctivagans, yet the entire con- 

 tour of the animal is strongly Lasiurian, and in fixing it thus we must de- 

 cide that the small premolar in the upper jaw, the rounded ear and hairy in- 

 terfemoral, are not essential characters to the genus. 



As a species it is intermediate between L. Graiji Tomes, and L. cinereus, 

 Pal. de Beau. It is larger than L. Grayi, and smaller than the majority 

 of specimens of L. cinereus; the thumb is small as in the former, but 

 the wing membrane extends to the base of toes as in the latter ; it is distinct 

 from both in the brown fur, in the high ear and the scantiness of the hair on 

 the interfemoral membrane. 



Habitat. Matamoras, Tamaulipas. L. B. Conch. 



MEASUREMENTS. 



Expanse 130 



Height of ear 06 



" " tragus 0-3 



Length of forearm 2-0 



" "tibia 0-9 



" " tail 2-0 



" " thumb 0-5 



" " foot 0-4 



" " longest finger 2 - 



Vespektilio nttidus, nob. 



Body small ; head and face very hairy, the nostrils separated by a narrow 

 slightly emarginate space ; ears longer than head, slightly emarginate on 

 outer edge, curving somewhat outwards, hairy at basal third behind, extend- 

 ing up a greater distance en the inner side ; tragus tapering, leaning a little 

 outwards, and about half the height of auricle ; lips extensively whiskered ; 

 thumb and foot small ;' interfemoral membrane ample ; calcaneum rather 

 long, with an excalcaneal membrane ; color of membranes darkish brown. 



Fur long and silky. Color plumbeus at base with russet tips behind and 

 lighter russet or ashy cinereus in front. Interfemoral membrane naked, ex- 

 cept the usual tuft at the base behind, and a few lightish hairs arranged trans- 

 versely in front. 

 Skull inflated, rather flatfish. 



6 1 4 16 

 Dentition, m-, c-, in.-, c-, m-=38. 

 6, 1 6 1 6 

 1862.] 



