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PROCEEDINGS OF THE NATIONAL MUSEUM 



This stingray does not appear to have been described very fully in 

 the past, and for that reason the following descriptive comments are 

 recorded, along with measurements in table 2. 



The disk is a httle longer than wide, evenly rounded; the tip of the 

 snout has a little soft knoblike projection beyond the outline of the 

 disk; the tail is longer than length of the disk, although the end of the 

 tail is almost invariably missing except on the embryos, and therefore 

 total length means very little; spu-acles about size of eye and located 

 just behind eyes; the space between the spiracles greater than inter- 



FlGURE 3. 



-Potamotrygon magdalenae (Dumerll) (U.S.N.M. No. 121665), 325 mm. in 

 total length, from Lago Tule. Sketch by author. 



