The Central American Thyroptera. 



Ill 



FIG. 3. Foot and uropatagium of 

 Thyroptera disci/era (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 

 free edge has also a narrow hairy border. 

 Antebrachial membrane hairy near base 

 and along humerus and fleshy part of 

 forearm, which in turn are covered with 

 hair. Uropatagium 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 abruptly 

 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 off from sole. 



Fur 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 ventrally, the hairs without 

 darker bases. Ears and membranes dusky brownish. 



Measurements. No. 51538, 9 a< 3-> Escondido 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; fourth finger 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. 



