Page:Natural History, Fishes.djvu/135

Rh vessel through the water must be deducted from the force exerted by the powerful animal. The weapon in this case had penetrated through one inch of sheathing, three inches of planking, and four inches and a half of the solid timber.

The Sword-fish is the furious enemy of the Whales, including the northern species and the Cachalot; and many accounts relate the rage and energy with which the armed warrior of the seas attacks his gigantic foe, and seeks to bury his weapon in his mighty sides. And in this animosity a motive has been sought for the suicidal assaults already mentioned, the Sword-fish mistaking the hull of the ship, a huge dark body moving through the water, for his enemy, and darting upon it with blind indiscriminating fury. It may be so: but Cuvier mentions a little fact, with which these attacks may not be unconnected. "Notwithstanding its formidable weapon, its great strength, and its almost incredible celerity, a small crustaceous animal penetrates the flesh of the Sword-fish, and sometimes so torments it that it dashes itself on the shore with mortal violence."

3. Centronotina. The form is oblong, or sometimes lengthened and slender; the fore part of the dorsal is superseded by a number of small free spines; the ventrals are present and perfect; the body is covered with very small scales. Seventy species are reckoned to belong to this group, which ranges over all seas. The most worthy of notice is the beautiful little Pilot-fish (Nancrates ductor, .), so called because of its constant attendance on Sharks, as well as on ships, a propensity as unaccountable as it is interesting. The fact is indubitable; we have ourselves witnessed