568 RAIID.E. 



thirteen inches ; breadth across the fins twenty-four inches ; 

 the eyes three inches apart, and five inches and a half from 

 the snout. The outline of the body much resembles that 

 of the Thornback, R. clavata ; snout a little prominent, 

 the margin waved to the extremity of the expansion, behind 

 rounded ; the eyes very small ; temporal orifices large : the 

 body covered with rough granulations, but altogether with- 

 out spines, either on its surface or about the eyes, except 

 a row that runs along two-thirds of the back, and down the 

 middle of the tail to the fins ; an irregular row of similar 

 hooked spines extends along each side of the tail ; along the 

 tail is a border on each side, like a membranous fin ; two 

 rounded fins towards the end of the tail, somewhat separated, 

 the hindmost one inch from the end, with which it is con- 

 tinuous by means of an elevated ridge. In the distribution 

 of its colours this is the most beautiful of the British Rays. 

 The upper surface is a light grey, with a lighter line running 

 along the back and middle of the tail, enclosing the central 

 row of spines. The disk is beautifully and regularly quar- 

 tered, first by three white lines enclosing each other, and 

 passing from near the eye circularly to near the extremity 

 of the expansion, the convexity of the arch inwards, and 

 consequently the shorter line nearer the margin ; on the 

 hinder edge of the disk, formed by the pectorals, are two 

 other lines passing from behind the expansion circularly to 

 the neighbourhood of the abdominal fins, the convexity of 

 the arch inwards ; on the more central part of the disk are 

 a few whitish spots, those of both sides answering to each 

 other ; the extreme edge of the disk posterior to its greatest 

 expansion, and also the abdominals, as well as the fin-like 

 margin of the tail, are edged with white. The nostrils have 

 a prominent expanded membrane ; width of the mouth three 

 inches ; teeth flat, like those of the Thornback ; mucous 

 orifices on the under surface numerous, and as if punctured 

 with a pin ; the colour of the skin a pure white. 



