RHIN013ATUS PRODUCTUS. 281 



tubercles of moderate sizes in a vertebral series, in two groups on each shoulder, 

 and in a row of smaller ones in front of the eye and above the orbit and spiracle. 

 A male of twenty-eight inches is not mature, probably thi-^ species is much 

 larger than R. percellens common in some of the same localities. 



Back light brown to ashy, uniform or with a spot of darker at the end of the 

 rostral cartilage, above and below. Whiter below, varying in amount of brown 

 at each side of the snout. Description taken from specimens of from eleven to 

 thirty-three inches brought from Rio Janeiro by the Thayer Expedition. 



Distinguished from R. percellens by the flatness of the crown, the straight 

 rostral ridges, the gradual narrowing of the groove, and by the lighter more 

 uniform color. 



Eastern Pacific species. 



RhINOBATUS PRODUCTUS. 



Rhinohatus producta Girard, 1854, Proc. Acad. nat. sci. Phil., p. 196. 



Rhinobatus productus Girard, 1858, Rept. Pacif. R. R. Fish., p. 370; Garman, 1881, Proc. U. S. nat. 



mus., 3, p. 517; Jordan & Gilbert, 1882, Bull. 16, U. S. nat. mus., p. 876; Jord. & Everm., 



1896, Bull. 47, U. S. nat. mus., p. 63. 



Disk broad, width six sevenths of the length; tail from bases of ventrals 

 little more than half the total length. Crown flattened, orbital edges prominent. 

 Snout produced, angle from opposite the orbits 60°; rostral cartilage broadening 

 toward the end ; ridges convergent to the middle, thence separated by a narrow 

 groove. A dermal flap with fringes on young of both sexes above the tip of the 

 snout. Nostrils little wider than the space separating them; anterior valve 

 narrow, lobe moderate, inner section extending one third of the distance to the 

 inner edge of the nostril and slightly turning forward at the end; outer section 

 of posterior valve narrow, inner section much larger. Mouth twice as wide 

 as the internarial space, one third the length of the snout, slightly arched forward 

 in the middle. Spiracles large, with two folds, outer somewhat larger. Dorsals 

 small, equal, base of first twice in its distance from the bases of the ventrals, 

 two and one half times in that from the second dorsal. Small tubercles sur- 

 rounded by enlarged scales in a vertebral series, in an inner and an outer group 

 on each shoulder and on the ridge around the orbit and above the spiracle. 

 Tubercles disappearing more or less completely with age. 



Olive-brown to ashy or reddish, clouded or blotched on the larger, fins 

 lighter; lower surfaces whitish, or blotched near the mouth, with an angular 

 spot of brown or black under the snout, fading with age. 



Off the coast of California. 



