THE FISHES OF MALABAR. 279 



Tho length of the disk in tho adult is three-fourths of its width, but in the immature it is less 

 than half. 



Snout moderately prominent, more so in the immature. Mouth rather arched. The distance 

 between the inner angles of the nostrils equals about half their longest diameter, but that between 

 their external angles is double what obtains from the centre to the point of the snout in the adult. 

 A depression exists in the upper jaw, external to the teeth, and a corresponding elevation in the 

 lower jaw. No denticle on the margin of the spiracles. 



Teeth — Tricuspidate, their central elevations being longer than their lateral ones, which are 

 horizontal. In both jaws tho teeth are confined to the central third. 



Fins — The anterior margin of the pectoral rather convex, and slightly exceeding in length that 

 of its posterior, which is slightly concave, its external angle conical, its internal moderately rounded. 

 Ventrals elongated, tetragonal, with their posterior angles rounded. Caudal shorter than the body 

 in the iinruature, but rather longer in the adult, its spine slender and situated on its anterior fifth. 



Colours — In the immature superiorly reddish brown, with numerous indistinct dark dots and 

 light spots : underneath dirty white. In the adult bluish brown above, dirty white underneath ; 

 tail annulated with dark brown and pinkish-white rings, in the centre of each of which last on the 

 upper surface is usually a round dark spot. 



Eaten by the Natives of Malabar, where however it is not common. It grows to as large as 

 four feet across the disk. 



Habitat — Red Sea, Seas of India, Malaysia, and China. 



Genus HYPOLOPHUS, Mill. & Henle. 



Form of the body the same as in the Trygons, but considerable difference in the mouth. Tail with a 

 fin which does not reach to its apex : upper fin absent. The centre of the lower jaw is pointed and pro- 

 jecting, and on each side has a cavity directed forwards : the margin of the upper jaw is excavated in the 

 centre for the purpose of receiving the point of the lower jaw, and also bulges on the sides. Teeth like 

 paving stones, hexagonal, broader than long : in the upper jaw the central ones are small, those at the sides 

 larger ; in the lower jaw they are of nearly equal size, but the external ones are the smallest. 



Hypolophus sephen. 



Raja sephen, Forsk. 17, no. 16. 

 Wolga Tenkee, Russell, pi. 3. 



Hypolophus sephen, Cantor, Catal. p. 429 ; Gray, Catal. Brit. Mus. p. 123 ; Blyth, 

 Journ. Asiatic Soc. xxix. p. 37, no. 14 ; Dumeril, Ich. g<5n. i. p. 616. 



Disk rhombic, angles rounded, the snout more pointed in the young than in the adult. The 

 distance from the snout to the mouth is two-sevenths of the length between the snout and the 

 anus. The distance between the nostrils equals half their distance from the snout. Under jaw 

 pointed in its centre, and on either side of its extremity is an elliptical cavity : the margin of 

 the upper jaw is excavated in its centre to receive the point of the lower jaw, whilst externally it 

 is very convex. Pupils of eyes transversely oval. 



Teeth — Like a pavement, hexagonal, broader than long : in the centre of the upper jaw they 



