Chap. X.] 



SWOED-FISHES. 



329 



somewhat flattened at the base, but tapering to a sharp 

 point. In strange inconsistence with its possession of so 

 formidable an armature, the general disposition of the 

 sword-fish is represented to be gentle and inoffensive ; 

 and although the fact of its assaults upon the whale has 

 been incontestably established, yet the motive for such 

 conflicts, and the causes of its enmity, are beyond con- 

 jecture. Competition for food is out of the question, as 

 the Xiphias can find its own supplies without rivalry on 

 the part of its gigantic antagonist ; and as to converting 

 the whale itself into food, the sword-fish, from the con- 

 struction of its mouth and the small size of its teeth, is 

 quite incapable of feeding on animals of such dimen- 

 sions. 



In the seas around Ceylon sword-fishes sometimes 

 attain to the length of twenty feet, and are distin- 

 guished by the unusual height of the dorsal fin. Those 

 both of the Atlantic and Mediterranean possess this 

 fin in its full proportions, only during the earlier 

 stages of their growth. Its dimensions even then are 

 much smaller than in the Indian species ; and it is a 

 curious fact that it gradually decreases as the fish ap- 

 proaches to maturity ; whereas in the seas around Ceylon, 

 it retains its full size throughout the entire period of 

 life. They raise it above the water, whilst dashing 

 along the surface in their rapid course ; and there is no 

 reason to doubt that it occasionally acts as a sail. 



The Indian species (which are provided with two long 

 and filamentous ventral fins) have been formed into the 

 genus Histiophorus ; to which belongs the individual 

 figured on the next page. It is distinguished from others 

 most closely allied to it, by having the immense dorsal 

 fin of one uniform dark violet colour ; whilst in its con- 



