DISCOBATUS SINENSIS. L'x<.) 



DlSCOBATUS SINENSIS. 



Plate 56, fig. 8 (heart); Plate 66. 



La Raie Chinoise Lacepede, 1798, Poissons, 1, p. 34, 157, pi. 2, f. 1. 



Rhina sinensis Schneider, 1801, Bloch Ichth., p. 352. 



Platyrhina sinensis Muller & Henle, 1841, Plagios., p. 125, pi. 44; Dumeril, 1865, Elasm., p. 576; 



CiuxTH., 1870, Cat. fishes Brit, mus., 8, p. 471. 

 Discobatus sinensis Gasman, 1881, Proc. U. S. nat. nius., 3, p. 522; Jord. & Fowler, 1903, Proc. U. S. 



nat. mus., 26, p. 647. 



Disk subround, deeper at the shoulders than at the head; head broad, de- 

 pressed, transversely concave. Snout short, very blunt, length less than twice 

 the width of the mouth, flexible. Mouth nearly straight; teeth very small, 112 

 rows on the upper jaws of the specimen described and 115 rows on the lower, 

 smooth to the touch, with sharp edge turned toward the mouth cavity. Nostrils 

 small, narrow, two thirds of the width of the interspace, nearly transverse; 

 anterior valve with a feeble outer section, a strong lobe, and a moderate inner 

 section extended somewhat on the internarial space; posterior valves with 

 outer section largest and curving around the outer end of the nostril, lobe small, 

 and inner section narrow, extending over half the width of the nasal chamber 

 and ending at the edge of the deep groove from the inner half of the nostril to 

 the angle of the mouth. Eyes small. Spiracles moderate, close to the eyes, 

 without folds, with a cartilage at each side. Aural openings close together. 

 Rostral cartilage short, broad, truncate, not extending half way to the end of the 

 snout, anteriorly continued by soft or semi cartilaginous rods, much as in Nar- 

 cacion and other electric rays. Pectorals very wide extending to the tip of the 

 snout, with more than half their width in front of the shoulder girdle, narrowly 

 separated in front. Ventrals broad, close to the pectorals. Dorsals equal, 

 rounded, length of base of the first dorsal about one third of the distance behind 

 the bases of the ventrals, little less than the distance from the second dorsal. 

 Caudal rather small, depth less than one third of its length, subtruncate, supra- 

 caudal and subcaudal being about equal in length. A dermal fold at each side 

 of the tail. Vent near the end of the forward half of the entire length. Scales 

 minute, compact, smooth to the touch, with scattered enlarged granules above 

 the body cavity, around each of the twenty or more small tubercles in the verte- 

 bral series, around each of those in the two pairs on each shoulder, in the pan- 

 above each spiracle and around each of the single ones at the front of the orbit. 

 Small tubercles in four or five series, and larger sharper granules, appear along 

 the outer edges of the anterior half of the pectorals. The inception of an electric 

 battery, from the ampullae, is clearly indicated, Plate 66. 



