35 § 
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 ( Xipliias 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 ( H 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 
