384 



THE PLAGIOSTOMIA. 



behind the caudal spine. Resembles D. sabinus in shape but is distinguished 

 by length of tail and by armature. A tubercle in the middle of the back becomes 

 gradually surrounded by others, thence they extend backward to the caudal spine. 



Coloration uniform. 



China: India. 



Dasybatus rudis. 



Trygon rudis Gunth., 1870, Cat. fishes Brit, mus., 8, p. 479. 



Disk broader than long, with very distinct outer angles. Snout somewhat 

 pointed; anterior margins concave. Back and tail rough with dense small 

 asperities, rather larger and stellate-based on the middle of the tail; no larger 

 tubercles. Tail one half longer than the disk, without a keel above, with a 

 fold below. 



Uniform brown. 



Old Calabar. 



Dasybatus sephen. 



Raia sephen Forskal, 1775, Descript. Anim., p. 17, no. 16; Bonnaterre, 1778, Ichth., p. 4; Gmelin, 



1789, Linn6 Syst., 1, p. 1508; Lac^p^de, 1798, Poissons, 1, p. 123; Schneider, 1801, Bloch Ichth., 



p. 364; Shaw, 1804, Zool., 5, p. 288. 

 Raia sp. Russell, 1803, Coromandel fiishes, 1, p. 2, no. 2, pi. 3. 

 Trygon sephen Cuv., 1817, Reg. anim., 2, p. 137; Peters, 1876, Sitzb. Berl. akad., p. 853; Gunther, 



1910, Sudsee fische, p. 494. 

 Trigon (Pastinachus) sephen Ruppell, 1828, Atlas fische, p. 52; 1835, Neue wirb. Abyssinien, Fische, 



p. 69. 

 Trigon forskdlii RtJppELL, 1828, Atlas fische, p. 53, pi. 13, f. 2. 

 Trygon wolga-tenkee Cuv., 1829, Reg. anim., 2, p. 399. 

 Hypolophus sephen MtJLLER & Henle, 1841, Plagios., p. 170; T. Cantor, 1849, Malay fishes, p. 429; 



Gray, 1851, Chondropterygii, p. 123; Bleeker, 1852, Verb. Bat. gen., 24, Plagios., p. 77; Blyth, 



1860, Journ. Asiat. see. Bengal, 29, p. 37; Dumeril, 1865, Elasm., p. 616; Day, 1865, Fishes 



Malabar, p. 279. 

 Trygon {Hypolophus) sephen GtJNTH , 1870, Cat. fishes Brit, mus., 8, p. 482; Klunzinger, 1871, Syn. 



fische, 2, p. 240; Day, 1878, Ind. fishes, p. 740, pi. 195, f. 2. 



Disk subquadrangular, much broader than long, angles obtuse, snout blunt, 

 margins shghtly convex. Mouth strongly undulate, upper dental lamina 

 •angularly bent forward, the upper jaws meeting in a sharp angle at the symphy- 

 sis; lower dental plate more flat, nearly three fourths as long as wide; teeth 

 unequal, largest wider than long. Five long papillae at the bottom of the mouth, 

 middle three elongate and close together. Anterior nasal valves joined and 

 free edged behind the isthmus in front of the mouth. Eyes prominent. Spir- 

 acles larger than the eyes. Ventrals short, broad, obhque on the hind margin, 

 angles blunt. Tail nearly three times the length of the disk, depressed and 

 rather stout anteriorly, slender and filamentary behind the spine; with a long 



