430 FISHES. 



sexual differences extend to tlie teeth, in addition to the 

 usual smoothness of skin observed in the females ; and 

 the male is further distinguished by a patch of tubercles 

 on the i^ectoral fins. In colour, this skate is pale grey 

 with black spots, the under surface nearly white, also 

 speckled with black. On the tail are two spineless dorsal 

 fins and three rows of tubercles. This skate grows to a 

 length of over 6 feet, a breadth of over 5 feet, and a 

 weight of between 150 and 200 lbs. It feeds largely on 

 whitings and crustaceans, and deposits its "purses," de- 

 void of tendrils, in early summer. 



Another skate of similar habits is the common Thornback 



or " Maid," which grows in our waters to a length of over 



-? feet, and is trawled or hooked in moderately 



Thornback. '-' ' ^ ^ J 



deep water. In colour it is brown, sometimes 



mottled, above, white beneath. The sexes differ in the 



same particulars as those of the skate, the teeth of the 

 male being pointed, those of the female flat. The upper 

 surface of the thornl^ack is, as the name implies, covered 

 at intervals with curved spines that point towards the tail. 



