BONY FISHES AND GANOIDS. 469 



are lateral in position. The members of the family are in the main fre- 

 quenters of the coasts of the Indian Ocean and the warmer parts of the 

 Atlantic, many of them resorting to the mouths of the larger rivers, and some 

 having taken to a completely fresh-water existence. The largest form is the 

 common meagre, which sometimes reaches a couple of yards in length. 

 Nearly all the species are fit for food; and the air-bladders of many are em- 

 ployed as a source of isinglass. The drum derives its name from the loud 

 sound the fish is capable of producing ; this sound being apparently due 

 to the striking together of the upper and lower pharyngeal bones, which 

 are heavily armed with flattened teeth. 



Although there appears occasionally to be some confusion between sword- 

 fishes and the very different saw-fishes, there ought to be no difficulty in 

 distinguishing the former at a glance from any other fish 

 that swims. This distinctive feature is the production of the Section 



upper jaw into the well-known " sword," which is wedge- XipMiformes. 

 shaped in form, and may exceed half the length of the rest Family 



of the head and body. Spear would, perhaps, have been a Xiphiidee. 

 more suitable title for this formidable weapon, with which 

 its owner can transfix an unfortunate cod or tunny, or drive it home in the 

 side of a whale as easily as we can thrust a table-fork into a cheese. Not 

 only so, but sword-fishes have 



often been known to drive -_ 



their weapon deep into the 

 planking of a ship's bottom, 

 probably from having mis- 

 taken the vessel for a whale. 

 Bathers, too, are by no 

 means safe from the on- 

 slaughts of these ruthless Fig. 8. -COMMON SWORD-FISH. 

 monsters, which occasionally 



grow to over a dozen feet in length. The kinds of sword-fishes are numer- 

 ous ; and they are divided into the two generic groups of Histiophorus and 

 XiphiaSj according to whether long and narrow pelvic fins are present or 

 absent. The dorsal fin, which may be either single or divided, has no dis- 

 tinct spinous portion ; it is always of considerable height, and in some cases 

 is so elevated as to project high above the water when the fish is swimming 

 near the surface, and there are stories current that it is occasionally used as 

 a sail. The skin of a sword-fish is either completely naked, or furnished with 

 minute rudimental scales. These fishes are chiefly surface-swimmers, and 

 are fond of lying in the sun to bask. According to Scoresby, the sword of 

 one of these fishes, found embedded in the hull of a ship at Liverpool, had 

 penetrated a sheet of copper, an oak plank two and a half inches in thickness, 

 a solid oak timber of seven and a half inches, and another plank of a couple 

 of inches. " The position of the bone was at the distance of four feet hori- 

 zontally from the stern, and two feet below the surface of the water when 

 the vessel was afloat. Hence it appeared that when the ship had been in 

 rapid progress through the water, she had been met and struck by a sword- 

 fish advancing in the opposite direction, by the shock of which, or by the 

 action of the water forced past the body of the animal by the vessel's progress, 

 the snout had been broken off and detached. The blow, though it must have 

 been singularly forcible, was not observed by any person in the ship." As a 

 further example of the power of the impact of these fish, it may be mentioned 



