180 BRITISH FISH AND FISHERIES. 



are the theme of many a sailor. Happily it is 

 not a frequent visitor to our coast, nor a long- 

 continued resident when it appears. 



Another species, the blue shark, (Carcharias 

 glaucus), remarkable for the slenderness of its 

 body, inhabits the Mediterranean, and period- 

 ically visits the Cornish coast, to the great 

 injury of the fishermen. Mr. Yarrell quotes 

 the following details, given by Mr. Couch : 

 " The blue shark is migratory, and I have 

 never known it arrive on the coast of Cornwall 

 before the middle of June ; but afterwards it 

 becomes so abundant, that I have known eleven 

 taken in one boat, and nine in another in one 

 day. The injury they inflict on the fisherman 

 is great, as they hover about the boats, watch 

 the lines, which they sometimes cut asunder, 

 without any obvious motive, and pursue the 

 fish that are drawn up. This, indeed, often 

 leads to their own destruction ; but when their 

 teeth do not deliver them from their difficulty 

 they have a singular method of proceeding, 

 which is, by rolling the body round, so as to 

 twist the line about them throughout its whole 

 length, and sometimes this is done in such a 

 complicated manner, that I have known a 

 fisherman give up any attempt to unroll it as a 

 hopeless task. To the pilchard drift-net the 



