UROTRYGON ASPIDURUS. 405 



skin smooth, median tubercles on tail 



brown uniform ..... aspidurus (page 405) 



Disk round 



tail little longer than disk 



skin with stellate based spines and tubercles 



brown, uniform mundus (page 406) 



Urotrygon chilensis. 



Urolojihtis chihnsis GiiNTHER, 1871, Proc. Zool. soc. London, p. 6.53, pi. 53. 



Disk broader than long, snout projecting a little, tail longer than the disk. 

 Disk smooth, but with tubercles along the median line, viz. three in a single series 

 on the middle of the back and two on the tail in front of the spine. 



Back nearly uniform brownish with a few indistinct specks of darker brown. 



Gunther's figure so closely represents the species later described as U. 

 aspidurus, differing mainly in the anterior position of some of the tubercles, as 

 to raise doubt of the validity of that species. 



Urotrygon goodei. 



Urohphus goodei Jordan & Bollman, 1890, Proc. U. S. nat. mus., 12, p. 151; Jord. & Everm., 1896, 

 Bull. 47, U. S. nat. mus., p. 81; Boulenqer, 1898, Boll. Mua. zool. anat. Torino, 13, no. 329, p. 1. 



Disk "to posterior base of pectorals" broader than long, anterior margins 

 little convex from the eyes outward. Tip of snout prominent, sharp. Eyes 

 small, four thirteenths of the snout. Interorbital width one half the snout, 

 equal the width of mouth. Ventrals projecting beyond the disk. Tail little 

 longer than disk; caudals elongate, from end of spine equal snout and eye. 



Body of young nearly smooth, excepting a spine or more on the middle of the 

 back and a few prickles on the snout. 



Brown, paler toward edges; caudal dark above, lighter edged. 



Described from young specimens, of from six to seven inches in length. 



Off the coast of Colombia, South America, Bay of Panama, and Bay of 

 Santa Helena. 



Urotrygon aspidurus. 



Plate 69, fig. 3 (skeleton). 



Urolophus aspidurus Jordan & Gilbert, 1882, Bull. U. S. fish, coram., 1, p. 307; Jord. & Everm., 

 1896, Bull. 47, U. S. nat. mus., p. 81; Gilbert & Starks, 1904, Mem. Cal. acad. sci., 4, p. 16. 



Disk broader than long, snout prominent, margins nearly straight for a 

 short distance in front, outer and posterior angles and margins rounded. Outer 



