THE HAMMER-HEADED SHARK, (Zygæna malleus,)
Is a very curious kind, having a transverse head like that of a hammer, with an eye at each extremity; and the Fox-Shark, or Thresher (Carcharias vulpes), is remarkable for the enormous length of the upper lobe of its tail, with which it is able to strike with tremendous force. This fish is one of the great enemies of the whale.
THE SKATE, (Raia batis,)
Is a species of the Ray, which was long disregarded in this country as a coarse, bad-tasted food, but which now appears upon our best tables. It is still, however, disregarded in Scotland and the north of England, where its flesh is principally used as a bait for other fish. On some parts of the continent, where these fish are caught in great abundance, they are dried for sale. The best season for Skate is the spring of the year. The body is broad and flat, of a brown colour on the back, and white on the lower side: the head is not distinct from the body, so that this fish and all belonging to this genus are apparently acephalous, or without a head. The peculiar form of this fish is owing to the large size of the pectoral fins, which extend from the head to the base of the tail, and are very wide in the middle, and so, combined with the sharpness of the snout, give the fish the shape known as rhomboidal. Dr. Monro has remarked, that in the gills of a large Skate there are upwards of one hundred and forty-four thousand subdivisions, or folds; and that the whole extent of this membrane, whose surface is nearly equal to that of the whole human body, may be seen by a microscope to be covered with a network of vessels, that are not only extremely minute, but exquisitely beautiful. The tail of the Skate is long, and generally prickly. The mouth is, as it were, paved with teeth, which are flat, and nearly square in shape. In the full-grown male the centre teeth are pointed, at least in some species. The eggs deposited by the female Skate are very similar to those laid by the shark, being in the shape of a square bag, with two horns at each end as here represented.