RHINOBATUS LENTIGINOSUS. 279 



Rhinobatus undulalus Olpers, 1831, Torpcd., p. 22; Muller & Henle, 1841, Plagios., p. 121, pi. 40; 



Castelnau, 1855, Anim., nouv., Poiss. p. 101; Dumeril, 1865, Elasm., p. 498; Kner, 1867, Nov. 



fischc, p. 417; Gunth., 1870, Cat. fishes Brit, mus., 8., p. 444. 

 Rhitiohalus glaucoslictus Olfers, 1831, Torpcd., p. 22. 

 Rhinobatus marcgravii Henle, 1834, Ueber Narcine, p. 34. 

 Rhinobatus percellens Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 63. 



Crown transversely concave, edges prominent, angle from the eyes forward 

 about 56° in an eighteen inch adult male. Rostral cartilage narrow in the middle, 

 broader toward the end ; ridges converging at the fontanel, in the posterior two 

 fifths of their length, thence separated by a narrow groove to the end. Mouth 

 slightly bent forward in the middle, nearly straight; width equal four elevenths of 

 its distance from the end of the snout. Dorsal fins small, equal, base of the first 

 two fifths of its distance from the bases of the ventrals, or from the base of the 

 second dorsal. The width of the nostrils equals their distance apart; anterior 

 valve small with an elongate lobe in the middle, inner section continued but 

 halfway to inner edge of nostril, the end slightly turned forward; inner section 

 of posterior valve widest. Spiracles large, with two folds, outer much the 

 larger. Scales minute with small keels, 3-8, of varying extent and position, 

 median more or less convergent. Small depressed spines, more prominent in 

 young, above the vertebrae to the second dorsal, in a pair on each shoulder, and 

 in a series from the inner edge of the spiracle to the front of the orbit. 



Back dark brown, more or less clouded and blotched or plain, white at each 

 side of the rostral cartilage, varying to transverse blotches, 8 or 9 on the tail 

 and sprinkled with small spots of white symmetrically arranged. An angular 

 spot of black below the end of the snout from which in most cases a black streak 

 extends back a short distance along each edge, balance of ventral surface white. 



Description from an 18 inch male nearly mature, from Rio Janeiro, one of 

 a number collected by the Thayer Expedition. 



West Indies to the Plata River. 



Rhinobatus lentiginosus. 



Plate 17. 



Rhinobatus lentiginosus Garman, 1880, Bull. M. C. Z., 6, p. 168; 1881, Proc. U. S. nat. mus., 3, p. 

 519; Jordan & Gilbert, 1882, Bull. 16, U. S. nat. mus., p. 65; Jord. & Everm., 1896, Bull. 47, 

 U. S. nat. mus., p. 62; 1900, ibid.. Atlas, pi. 8 «fe 9, f. 28. 



Crown transversely concave, edges moderately prominent. Snout long, 

 angle from the orbits forward 54°, point blunted. Groove between the rostral 

 ridges narrowing regularly from the sk^ull; ridges widening forward and the carti- 



