The Dog-fish, which sometimes attains the length of between three and four feet, is exceedingly voracious. It feeds upon other fish, of which it destroys great quantities; it does not hesitate to attack the fishermen, and especially bathers in the sea. It places itself in ambush, like the Raias, in order to attack its prey.
The flesh of the Dog-fish is hard, smells of musk, and is rarely eaten; but the skin becomes an article of commerce, and is known as shagrin, being, like the skin of the Shark, used for making spectacle-cases and for other ornamental purposes, for which its green color and high polish recommend it.
There is a smaller species than the preceding, which haunts rocky shores, where it lies in wait for its prey. Its spots are larger and more scattered, and its ventral fins are nearly square. It feeds on Molluscs, Crustaceans, and small Fishes.
The Hammerhead is chiefly distinguished by the singular form of its head, which is flattened horizontally, and the sides prolonged, giving it the appearance of the head of a hammer. The eyes of this Fish are placed at the extremity of these hammer points of the head; they are grey, projecting, and the iris is gold-colored. When the animal is irritated, the colors of the iris become like flame, to the horror of the fishermen who behold them.
Beneath the head and near to the junction of the trunk is the mouth, which is semi-circular, and furnished on each jaw with three or four rows of large teeth pointed and barbed on two sides.
The most common species in our seas is long and slender in the body, which is grey, and the head is black. It usually attains the length of eleven or twelve feet, weighing occasionally nearly five hundred pounds. Its boldness and voracity, and craving for blood, are more remarkable than its size. If the Hammerhead has not the strength of the Shark, it surpasses it in fury; few Fishes are better known to sailors in consequence of its striking form. Its voracity often brings it round ships and near the coast. Its visits impress themselves on the memory of the sailor, and he loves to relate his hair-breadth escape from the meeting.
The Saw-fish is distinguished from all other known Fishes by the formidable arm which it carries in its head. This weapon is a prolongation of the nose, which, in place of being rounded off or reduced to a point, forms a long, straight, strong, sword-like termination, flat on both sides, and on the two edges furnished with numerous strong teeth, giving the appearance of a double saw, or one with teeth on both edges.