THE SHORE FISHES OF PERU 63 



exist, as lima is described as more or less uniformly grayish or brownish. 

 The prominent dark blotches and spots in chilcae would scarcely have 

 been overlooked. The disk is rounder anteriorly than in the other 

 specimens at hand; the upper surface is smoother; and it alone has 

 no sharp spines, except the ones toward outer parts of pectorals, 

 which probably are present in all males. The spines on pectorals are 

 in a band, however, and not arranged in rows as in P. caudispina and 

 in P. brevicaudatus. 



Range. — The type and only specimen known was secured by the 

 Mission on sandy botton with a seine in Chilca Bay. 



Family DASYATIDAE: Sting Rays 



Head and body depressed, forming with the pectoral fins a broad 

 disk; pectorals meeting in front of cranium, without a supporting 

 rostral cartilage; tail long or short, with or without a spine; spiracles 

 large, close behind eyes, superior; nostrils confluent, with a broad flap 

 in front of mouth; mouth transverse, more or less curved ; teeth numer- 

 ous, in pavement, usually with ridges or small cusps, skin smooth, or 

 rough with spines and tubercles. 



Three genera are represented in the Peruvian collections studied. 



KEY TO THE GENERA 



c. Tail very long, whiplike, with at least one strong serrated spine. 



Dasyatis (p. 63) 

 aa. Tail shorter, not whiplike, about equal to or not greatly exceeding length 



of disk; a narrow caudal fin present XTrotrygon (p. 64) 



aaa. Tail very short, with no caudal fin, with a membranous fold above and some- 

 times below Pteroplatea (p. 71) 



Genus DASYATIS Rafinesque, 1810 



Whiptail Sting Rays 



Disk subtriangular to subcircular; tail long, whiplike, with at least 

 one strong serrated spine, with or without dermal folds behind the 

 spine; upper surface usually more or less spinous or prickly, rarely 

 smooth; mouth usually with a few papillae on inside at base of lower 

 jaw; teeth small, paved; pectorals meeting in front of skull. 



One species is known from Peru. 



DASYATIS BREVIS (Carman) 



Rata 



Trygon brevis Garman, 1880, p. 171, Paita, Peru (original description). 



Dasybatis brevis Garman, 1913, p. 396, pi. 32, figs. 5, 6, Paita, Peru; San Diego, 

 Calif, (synonymy; description; range). 



Dasyatis brevis Nichols and Murphy, 1922, p. 504, Paracas Bay, Peru (notes on 

 local abundance, and wounds from spine). — Fowler, 1941a, p. 228 (refer- 

 ences). — Beebe and Tee-Van, 1941, p. 260, fig. 22 (range; field characters; 

 size; discussion; synonymy). 



Disk somewhat broader than long, its anterolateral margins nearly 



