358 SPINY-FINNED GROUP. 



the sword-fishes are further characterised by the elongate and compressed body, 

 the laterally-placed eyes, and the deep cleft of the mouth. Teeth are either absent 

 or rudimentary ; and scales are likewise wanting, or represented merely by small 

 rudimental structures. The dorsal fin is either single or divided, but has no 

 distinct spinous portion ; and the pelvis, if present at all, takes the form of long, 

 rod-like, thoracically-situated appendages. There are seven branchiostegal rays, 

 and an air-bladder is present. In the adult the sword is formed by the coalescence 

 of the premaxillse, vomer, and ethmoid, and is rough on the under surface from 

 the presence of rudimental teeth. The sword-fishes are divided into the genera 

 Xiphias and Histiophorus, according to the absence or presence of pelvic fins ; 

 these appendages in the latter being in the form of from one to three rays. There 

 is considerable variation in the height of the dorsal fin, which is frequently so 

 lofty as to project some distance above the water when the fish is swimming near 

 the surface, and even, it is said, to answer the purpose of a sail. In the young, 

 this fin is much higher in proportion to the length of the body than it is in 

 the adult. In very young examples of the typical genus the beak is comparatively 

 long, there are conical prominences on the edge of the supraorbital, the occiput 

 is devoid of a spine, and there are two short, tooth-like processes at the angle of 

 the preopercular. In Histiophorus, on the other hand, the beak at a corresponding 

 age is much shorter ; the supraorbital edge is finely denticulated, or smooth ; and 

 there is a bony spine on each side of the occiput, and at the angle of the preopercular. 

 Although they are frequently not more than 4 to 6 feet in length, sword-fishes 

 may measure as much as from 12 to 15 feet, and the sword itself may exceed a 

 yard in length. The common European sword-fish {Xiphias gladius), which is 

 occasionally taken on the British coasts, ranges from the European seas to the 

 opposite side of the Atlantic ; while to the southward it occurs off the northern 

 and western coasts of Africa. Histiophorus, on the other hand, seems to be 

 confined to the Pacific and Indian Oceans, ranging eastwards to Japan. Of the 

 three Indian species, the spotted Indian sword-fish {11. gladius) is distinguished 

 by the dorsal fin being much higher than the body, and marked with dark blue 

 spots on a lighter ground of the same colour ; the body being bluish grey above, 

 and lighter beneath. On the other hand, in the black-finned sword-fish {H. 

 immaculatus) the general colour of the body is dull grey, and the dorsal and 

 anal fins are blackish. ' The third species {H. brevirostris) has the dorsal fin lower 

 than the depth of the body ; the general colour being grey, but the dorsal and 

 pectoral fins tipped with black. 



Mainly pelagic in their habits, sword-fishes are among the most predaceous 

 and savage of the monsters of the deep, transfixing their ordinary prey, which 

 includes cod and tunny, with their formidable sword, and likewise attacking 

 whales with the same weapon. In such conflicts, the sword-fish, after making 

 repeated stabs, generally comes out victorious, and the whale succumbs to his 

 comparatively diminutive antagonist. Occasionally, however, one of these fishes 

 appears to mistake a ship's bottom for a whale, and thereupon promptly charges 

 it, sending the sword crashing through several inches of solid timber. In such 

 cases it may happen that the sword-fish cannot withdraw its weapon, which is 

 then broken off short in the struggles of its owner to escape. One thing we 



