The Central American Thyroptera. 



Ill 



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Fig. 3.— Foot and uropatagiura of 



Thyroptera discifera (X 2). 



Membranes. — The membranes are thin and semitransparent, broad and 

 ample. Wings attached at middle of \ 

 claws, sparsely hairy from sides of body -^^^ 

 to line connecting elbow and knee. The ^^ j 

 free edge has also a narrow hairy border. /J^- ^ 

 Antebrachial membrane hairy near base f 5? 



and along humerus and fleshy part of ' ^^ 



forearm, Avhich in turn are covered with J^ 



hair. Uroi^atagium sparsely haired 

 throughout on dorsal surface, otherwise 

 naked, except at extreme base and along 

 veins on ventral surface. 



Feet. — The feet are small, weak, and 

 so turned outward as to be nearly in line with calcar (Fig. 3). Toes with 

 two phalanges, of which the second is very small and serves merely to 

 support the long claw. All the fingers are bound together by membrane 



to about the middle of the claws, 

 while the third and fourth digits 

 are firmly united, so that the two 

 claws, although really separate, 

 form what is apparently one strong 

 nail, shorter and more abruj^tly 

 curved than the others (Fig. 4). 

 Calcar strong, distinct, longer than 

 free border of uropatagium, termi- 

 nating in a small lobule and bear- 

 ing a well-formed keel, supported 

 by one strong cartilaginous pro- 

 cess. Sucking disk circular, the 

 margin next the phalanges distinct, that toward the keel not sharply 

 marked oft' from sole. 



Far and color. — In distribution, the fur is peculiar in its extension on 

 the wings and dorsal surface of the interfemoral membrane. Color dull 

 yellowish brown throughout, scarcely paler ventralh', the hairs without 

 darker bases. Ears and membranes dusky brownish. 



Measurements. — No. 51538, $ ad., Es,condido River, Nicaragua; total 

 length, 66 mm. ; head and body, 37.6 ; tail, 26 ; free tip of tail, 2 ; femur, 13 ; 

 tibia, 13.4; foot, 4 ; forearm, 31 ; third finger — metacarp., 29.8 ; first ph., 

 14; second ph., 7.8; fourthfinger — metacarp., 28.6; first ph., 10; second 

 ph., 4.6; fifth finger — metacarp., 26; first ph., 8; second ph., 5.6; ear, 

 11.6; width of ear, 12; tragus, 4 ; diameter of disk on thumb, 3 ; diam- 

 eter of disk on foot, 2. 



No. 51539, $ ad., same locality and date; total length, 65; head and 

 body, 38; tail, 26; free tip of tail, 1.8; femur, 14; tibia, 14.8; foot, 4.8 ; 

 forearm, 31.6; third finger — metacarp., 29; first ph., 13.4; second ph., 

 8.4; fourth finger — metacarp., 29; first ph., 9; second ph., 5.4; fifth 

 finger— metacarp., 25.6; first ph., 7.4; second ph., 6; ear, 12; width of 

 ear, 12; tragus, 3.6; diameter of disk on thumb, 3.4; diameter of disk 

 on foot, 2. 



Fig. 4. — Right foot of Thyroptera disci/era 

 greatly enlarged to show syndactylism of 

 third and fourth digits. 



