igoS.] 



Records of the Indian Museum. 



177 



(2) Behind the dorsal fin is a remarkable globular swelling 



of the size of a man's fist (fig. 3, plate v). This is 

 not present in the other species. 



(3) The denticles of the skin consist of a stellate base, 



usually six-rayed, which bears a multifid spine. 



Other specific characters cannot be defined as the specimen was 

 incomplete. 



The diagram, plate x, fig 2, which is drawn to scale, shows 

 the principal measurements of the head. 



The upper surface of the head and adjacent portions of the 

 disc were of a dark greenish grey colour contrasting sharply with 

 the pure white of the oral surface. 



Fig. I. — Teeth of Ceratoptera orissa, sp. nov. 



The upper surface of the cephalic flippers and the sides of the 

 head were white, as were the lower two- thirds of the ocular promi- 

 nences. 



The mouth was overhung by a thin curtain or velum of 

 white skin ; the depth of this curtain was about four inches except 

 towards the middle where it was considerably reduced, allowing a 

 view of the interior of the mouth. 



This velum, which is analogous to an upper lip, is quite distinct 

 from the broad nasal flap ; it resembles that structure and is at- 

 tached behind it. Figure 2, plate v, shows these features, as well 

 as the band of teeth on the lower jaw. Other measurements are 

 as follows : — 



Between the nostrils 



Width of mouth 



Dimension of the band of teeth 



Greatest diameter of eyeball 



Corneal aperture of eye . . 



Greatest diameter of spiracle 



The cranium of Ceratoptera orissa consists of a single lamina of 

 cartilage measuring 95 cms. in breadth but only 20 in length in the 

 middle line. The outer ends of this lamina turn forwards as two 

 spatulate projections which lie over and support the bases of the 





6t 



cms. 







55 



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47 by 2 '5 



cms 





7 



J J 







2 



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5 



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