GAEMAN : NEW PLAGIOSTOMIA AND CHISMOPNEA. 253 



Origin of dorsal fin opposite the ends of the bases of the ventrals ; 

 back smooth ; 



disk less than twice as wide as long ; 



green brown-edged ocelli on hinder part of disk milvus. 



Disk twice as broad as long ; 



blue cross-bands, about five, disappearing with age, no spots . nichofii. 

 Origin of dorsal fin backward from ends of bases of ventral fins ■ 

 back smooth ; 



disk less than twice as broad as long ; 

 brownish with networks of black lines, anteriorly in bands . vespertilio. 



Rhinobatus rasus, sp. nov. 



The snout of this species is pointed and elongate, more than three and a half 

 times the width of the crown between the orbits. The rostral ridges are close 

 together, parallel in most of their length, and show little or nothing of a groove 

 between them. The crown is broad and has little convexity. The eyes are small 

 and prominent. Each spiracle is as large as the eye and has two folds on the 

 hind margin, the inner one of which is the smaller. In width the nostrils are 

 about one-fourth of the snout. The anterior nasal valve is narrow and does not 

 extend upon the iuternarial space. Mouth, in width more than one-third of the 

 length of the snout, nearly straight. Entire upper surface covered with fine scales, 

 which are larger near the vertebral column and on the top of the head. A row of 

 larger tubercular scales on each rostral ridge ; two stronger tubercles in front of 

 each eye, one or more at the inner edge of each spiracle, a row of nineteen large 

 tubercles from the back of the head to the first dorsal fin, and a pair, the outer 

 one of which is smaller, on each shoulder. Lower surfaces entirely covered by 

 fine shagreen. Of the fins the hinder angle on each dorsal is pointed and the 

 hinder margins are concave ; the caudal is narrow. 



Brownish, whitish at each side of the rostrum, with a darker area opposite the 

 shoulder girdle on the base of each pectoral fiu, and with a clouded spot of darker 

 below the end of the snout on an otherwise uniform whitish lower surface. 



Type Cat. 235 M. C. Z., from Akkra, Gulf of Guinea. 



This species is distinguished from the species R. percellens and R. rhinobatos 

 by the pointed snout, the narrow nasal valve, the enlarged scales on the middle of 

 the upper surfaces, and especially by the rostral ridges. 



Rhinobatus acutus, sp. nov. 



Rhinobatus actitus is readily distinguished from R. rhinobatos by its very long 

 and more pointed snout, by its narrow nostrils, and by its wide internarial space, 

 which last is one and one-third times the widtli of the nostrils ; these features also 

 separate this form from any other of the Indo-Asiatic species. Snout long, length 

 little less than one-fourth of the total length, ending in a sharp point. Mouth 

 nearly midway between the pelvis and the end of the snout, slightly arched, in 

 width little less than one-third of the length of the snout. Rostral ridges slender, 

 not widened at the end, confluent at about one-fifth of their length from their 



