OF THE BRITISH ISLANDS. 41 



A length of from eighteen to twenty-two inches, with a 

 weight of from twelve to eighteen pounds, represent the 

 largest proportions which the John Dory attains upon our 

 coasts. It enjoys an almost cosmopolitan distribution, 

 extending from Norway throughout the Atlantic ; and a 

 variety of the same species, according to some autho- 

 rities, is met with at the Cape of Good Hope, South 

 Australia, and Japan. 



FAMILY XIV.— Sword-Fishes (Xiphiidcz). 



Body compressed, naked, or with rudimentary scales ; 

 the upper jaw, comprising the ethmoid, vomerine and pre- 

 maxillary bones, produced into an ensiform or sword-shaped 

 process ; teeth absent, or very minute ; branchiostegal rays 

 seven in number. 



The European Sword-fish {Xiphias gladius), No. 53, 

 common in the Mediterranean, where it is the subject of an 

 important fishing industry, is not an unfrequent visitor to 

 our own shores. It is one of the largest Acanthopterygian 

 fishes, attaining to a length of twelve or fifteen feet and 

 upwards, in aspect not unlike a Tunny, having superadded 

 to it the very formidable sword-like rostrum from which it 

 takes its name. The precise use of this structure, except 

 as a weapon of offence, is one of the zoological problems 

 that have yet to be solved. According to ancient tradition 

 the fish is accustomed to use its sword for impaling the 

 fish, upon which it feeds, like larks upon a spit ; a difficulty 

 connected with such an interpretation is, however, an ex- 

 planation of the method by which after capture in such 

 manner he detaches his prey and conveys it to his 

 mouth. Modern writers have suggested that it uses its 



