RHINOBATUS BOUGAINVILLII. 277 



53°, on an adult male of thirty-five inches. Crown somewhat concave, e<li:c- 

 of slight prominence. Rostral cartilage strong; ridges distinct to near the end, 

 converging more rapidly in the third of their length nearest the skull. Inter- 

 narial space one half, and nostril two thirds of the width of the mouth. Anterior 

 nasal valve moderate, inner of the sections wider, extending halfway from tin- 

 lobe to the inner edge of the nostril, thence turning forward; posterior valve 

 well developed, inner section largest, much wider than the outer. Mouth bent 

 forward in the middle third, width two sevenths of the length of the snout. 

 Spiracle smaller than the eye, with two prominent folds, outer fold twice the size 

 of the inner. Anterior dorsal little larger, base more than one third of the 

 distance from the bases of the ventrals, or three eighths of that from the second 

 dorsal. Caudal moderate, outlines resembling those of R. planiceps, Plate 17, 

 fig. 3. Scales minute, smooth to the touch, likewise the very small tubercles 

 of the vertebral series and that around the eye, probably rougher and com- 

 paratively larger in the young. 



Back rusty brown ; fins with a light edging. Lower surface brownish yellow. 

 Whitish spaces at the sides of the rostrum are probably to be seen on the younger 

 stages. 



Japan. 



Australian species. 



RHINOBATUS BOUGAINVILLII. 



Rhiiwbatus (Syrrhina) bougairwillii Muller & Hbnle, 1841, Plagios., p. 117; Dumeril, 1865, Elasm., 

 p. 491, pi. 10, f. 1; Gunth., 1870, Cat. fishes Brit, mus., 8, p. 445; Ogilbt, 1888, Cat., p. 15. 



Disk little longer than wide. Snout long, tapering to a point, little less in 

 length than twice the distance between the outer edges of the nostrils. Rostral 

 ridges rapidly converging at the sides of the fontanel, thence straight. Nostrils 

 wider than then distance apart. Anterior nasal valve not continued beyond 

 the inner edge of the nostril; posterior valve reaching a little beyond the middle 

 of the nostril. Mouth strongly curved forward in the middle; median teeth 

 small, bordered at each side by a group of larger, pointed teeth, outer teeth in 

 both jaws smaller. Spiracles large, without folds. Scales minute, smooth; 

 slightly prominent spines in front of the eye, an outer and one or two inner above 

 each shoulder, and in a remotely spaced series above the vertebrae. 



Uniform blackish brown, above and below or with lighter and darker spots 

 on the tail. 



Port Jackson. 



