I9IO. ScHARFF. — The File-Fish in h'ish Waters. 29 



THE FII.K-FISH IN IRISH WATERS. 



BY R. F. SCHARFF, PH.D , M.R.I.A. 



[plate I.] 



A specimen of this fish {Balistes capriscus) was taken in a 

 trawl near the entrance of Courtmacsherry Bay, Co. Cork, in 

 8 fathoms of water, and sent to the Irish National Museum by 

 Mr. J. Driscol of Courtmacsherry. Having on several 

 occasions captured rare kinds of fish for the Museum, he 

 knew that this was something quite out of the common and 

 despatched it without delay, on the 24th of September last, 

 to Dublin. 



The sketch (Plate 1) of the fish, by Miss McNab, shows 

 clearly its distinguishing features, nameh^ the small mouth 

 and powerful teeth, the thick plate-like scales, and the 

 peculiar spine in front of the first dorsal fin. The second 

 much shorter spine has the power of locking or fixing the 

 first in position, thus acting as a trigger. This has given 

 rise to the name of '• Trigger-fish " a term often employed for 

 this species. The name "File-fish" is derived from the 

 roughness of the front surface of the large spine, a feature which 

 will be readily noticed in the annexed plate. The strong teeth 

 suggest a carnivorous habit, and indeed the File-fish is a 

 shallow-water species living chiefly on shells which it nibbles 

 off the rocks and crushes with its powerful jaws. 



The species figured seems to be; identical with the American 

 so-called " Eeather-jacket" (Balistes carolhie^isis)^ which is so 

 common on the coasts of some of the southern United States. 

 It is less abundant in the Mediterranean, and the question 

 arises if this Irish File-fish is a stray visitor from a 

 Mediterranean or from an American stock. 



Only once before has this fish been noticed on the Irish 

 coast, namel}^ in 1853, by Prof. Melville, near Galway; and 

 that specimen I believe is no longer in existence. Our present 

 fish measures about 9 inches in length. The colour had 

 unfortunately entirely faded when it reached me. It is 

 generally of an olive-grey tinge. During life there are 

 vividly blue and violet spots about the head, the first dorsal 

 fin being bluish, and the second yellow, spotted with blue. 

 These brilliant colours quickly disappear after death. 



Natioual Museum, DubUu. 



