332 CHONDROPTERYGII. RAY FAMILY. 



taken in skate-nets set in deep water, more especi- 

 ally in tlie months of May and June, when a few 

 may be seen in the Edinburgh market along with 

 grey-skate and thornbacks. It is known to fisher- 

 men under the name of rough-flapper^ and its flesh 

 is considered inferior as food to that of the other 

 species of skate, it being soft and dry. It feeds on 

 small star-fish and crustaceous animals in general. 



(Sp. 243.) R. damia. The Thornback. One of 

 the best known fishes of this tribe, as it is generally 

 dispersed throughout the British seas, and almost 

 everywhere captured in large numbers. There is no 

 chance of it being confounded with any of the spe- 

 cies already noticed, as it is at once known by being 

 studded, at intervals, all over the surface, with oval 

 or rounded tubercles which form the base of a strong 



a 



curved spine. The tail is armed with from one to 

 five rows of such tubercular spines, and a single row 

 runs up the dorsal ridge. Varieties occur in which 

 there are two rows of spines on the back, and no 

 fewer than seven rows on the tail. These spines 

 exist on the under side as well as the upper, but in 

 fewer numbers, and are chiefly observed in old fish. 

 The flesh of the Thornback is held in good estima- 

 tion ; it is in best condition for the table in Novem- 

 ber. The fish, however, is obtained in greatest plenty 

 during spring and summer, when it frequents the 

 shallower waters for the purpose of ejecting its ova. 

 Flounders appear to be its favourite prey ; also her- 

 ring and sand-eels ; occasionally it feeds on crabs. 

 Young individuals, that is, before they arrive at the 



