On a new Ceratopterine Eagle-Ray. 227 



XXIII. Description of a new Ceratopterine Eagle-Ray from 

 Jamaica. By Gr. A. BOULENGER, F.R.S. 



AMONG some Fishes brought home from Jamaica by the 

 Rev. J. Seed Roberts, who for many years has been paying 

 special attention to the fish fauna of that colony, there was a 

 Ceratopterine Ray which neither Mr. Roberts nor myself 

 succeeded in identifying. It has much in common with 

 Bancroft's Ceplialopterus hypostomus, described from Jamaica 

 in 1830, but is at once distinguished by the absence of teeth 

 in the lower jaw, which precludes our referring it to the 

 genus DicerobatiSj in which teeth are present in both jaws. 

 The allied genus Ceratoptera agrees in this, that teeth are 

 developed in one of the jaws only, but it is the lower instead 

 of the upper that bears them ; and, besides, the position of 

 the mouth and the shape of the pectoral fin are entirely 

 different. I therefore find myself compelled to propose a 

 new genus for the reception of the Ray, with which I wish to 

 associate the name of its discoverer. 



CERATOBATIS, gen. nov. 



Like Dicerobatisj Blainv., but teeth restricted to the upper 

 jaw. 



Ceratobatis Robertsii, sp. n. 



The band of teeth occupying only half the width of the 

 mouth, its width 10 times in its length ; teeth tessellated, 

 hexagonal, 2 to 3 times as broad as long, rugose with nume- 

 rous obtuse ridges. Mouth inferior, wide. Pupil vertically 

 elliptic. Body smooth; pectoral fins with nearly straight, 

 slightly convex anterior and slightly concave posterior border. 

 Cephalic fins measuring a little less than the width of the 

 mouth ; spiracles behind the eyes. The space between the 

 last branchial clefts one fourth that between the first. 

 Dorsal fin between the ventrals. Tail slender, without spine, 

 nearly twice as long as the body. 



millim. 



Length of disk, without cephalic appendages 350 



Width of disk 780 



Cephalic fin 90 



Width of mouth 105 



Diameter of eye 12 



Ventral fin 70 



Tail . . 620 



