64 BULLETIN ISO, UNITED STATES NATIONAL MUSEUM 



straight and oblique, meeting at a very broad angle at snout, convex 

 elsewhere, broadest opposite about the third pair of gill slits, its 

 width in total length 2.2; length from tip of snout to posterior 

 margin of disk 2.45; length anterior to axil of pectoral 2.7; length 

 anterior to vent 2.85, length posterior to vent (tail) 1.6; tail about 

 twice as wide as deep at base, nearly round and very slender posterior 

 to caudal spine, with a rather prominent dermal fold above, posterior 

 to spine, the fold scarcely longer than snout in advance of mouth; a 

 broader and longer fold below, beginning somewhat in advance of 

 base of spine, coterminal with the dorsal fold; the main spine with 

 finely serrate lateral edges, about equal to length of snout in advance 

 of mouth, with a short auxiliary spine at base; tip of snout scarcely 

 exserted, its length to eye 4.7 in length anterior to axil of pectoral, 

 its preoral length 5.2; eye notably smaller than spiracle, 15.3; inter- 

 orbital 9.2; mouth transverse wav}?^, its width 8.35; teeth in pavement, 

 flat, without cusps; disk smooth, except for a single short strong 

 nuchal spine; ventral broadly rounded, overlapped by pectoral, its 

 outer distal angle scarcely extending beyond margin of disk, its great- 

 est length 4.5 in length anterior to axil of pectoral. 



Color uniform bluish gray above; pale underneath; tail posterior 

 to dermal folds black. 



This ray is represented by a single specimen, a female 625 mm. 

 long, on which the foregoing description is based. No specimens are 

 available for comparison. According to published accounts the 

 specimen at hand has a rather longer tail and fewer spines than others 

 described and figured. However, the specimen is smaller, which may 

 account for the differences. Garman (1913, p. 397) reported five 

 buccal papillae. I am able to find only three in the specimen at hand. 



The specimen in the present collection was taken with a seine in 

 Independencia Bay at Lagunilla. It is stated in the report of the 

 Mission (1943, p. 286), that a "number of sting rays were taken" 

 and, further, "These rayas are considered very dangerous by the 

 fishermen and cases are on record where they have caused severe 

 injury, if not death, to persons hit by the stings." As the rays were 

 not identified as to species in the field, more than one species may be 

 involved. According to Beebe and Tee-Van (1941, p. 261), D. brevis 

 attains a length of at least 180 cm. 



Range. — San Diego, Calif., to Independencia Bay, Peru, except 

 Central America. 



Genus UROTRYGON Gill, 1863 



Rayas 



Disk more or less subcircular; snout more or less produced, rather 

 pointed; mouth transverse, somewhat wavy; teeth numerous, in pave- 

 ment, broader than long, with or without small cusps; tail about equal 

 to or not greatly exceeding length of disk, depressed at base, with a 



