282 THE PLAGIOSTOMIA. 



Rhinobatis glaucostigma. 



Rhinobatis glaucosiigma Jordan & Gilbert, 1SS3, Proc. U. S. nat. mus., 5, p. 210; Jord. & Everm., 

 1896, Bull. 47, U. S. nat. mus., p. 62. 



Snout produced, blunted, length less than twice the distance between the 

 outer angles of the nostrils, about two fifths of the length of the disk. Rostral 

 ridges separated, converging forward. Spiracles large, smaller than the eyes, 

 with two folds. Dorsals about equal. Small tubercles in the vertebral series, 

 around the orbit and on each shoulder one or two. 



Greyish, lighter at each side of the rostrum, with many large spots, as large 

 as the eye, symmetrically arranged, slaty or bluish; a blackish spot below the end 

 of the snout. 



Reaches a length of thirty inches. 



Gulf of California. 



Apparently closely allied to R. horkelii and R. leucorrhynchus ; distinguished 

 by the spots. 



Rhinobatus spinosus. 



Rhinobatus spinosus Guntii., 1870, Cat. fishes Brit, mus., 8, p. 518. 



Anterior nasal valve not dilated laterally. Snout much produced, the dis- 

 tance between the outer angles of the nostrils being one half of that between the 

 mouth and the end of the snout. The rostral ridges are confluent, very narrow, 

 with a very small and short groove at the base," and in their entire length provided 

 with spines. Mouth nearly straight. Compressed spines with dilated base 

 along the median line of the back, on the shoulder, and above the eye and spir- 

 acle; the entire upper surface rough. Snout white. 



Described from a stuffed specimen, 13 inches long. 



Mexico. 



Rhinobatus leucorhynchus. 



Rhinobatus leucorhynchus GtJNTH., 1866, Proc. Zool. soc. Lond., p. 604; 1867, Trans. Zool. soc. Lond., 

 6, p. 490; 1870, Cat. fishes Brit, mus., 8, p. 444, fig. 1; Garman, 1881, Proc. U. S. nat. mus., 3, 

 p. 517; Jord. & Everm., 1896, Bull. 47, U. S. nat. mus., p. 62; Gilbert & Starks, 1903, Mem. Cal. 

 acad. sci., 4, p. 14. 



Disk broad, width about seven eighths of the length; snout strong, pointed, 

 length equal half the width of the disk. Rostral cartilage strong, tapering; 

 ridges straight, separated at the foramen by the width of the spiracle, thence 

 converging regularly to one third of this width at the ends. Nostrils one fourth 



