SQUALUS, the shark, in natural his tory, a genus of fishes of the order Car tilaginei. Generic character : mouth un der the fore part of the head, with teeth disposed in rows, and partly moveable and partly fixed; generally five spiracles, at the sides of the neck, of a semilunar shape ; body oblong, rather cylindric and rough, with tender prickles. These ani mals are never found in rivers or lakes, inhabiting only the sea, and carrying terror and destruction wherever they ap pear. They grow, in some species, to the weight of three or four thousand pounds. They occasionally emit a phos phoric illumination, visible by night. They produce their young alive, several at a birth, but every one inclosed in a transparent horn-like substance, length ened at the extremity into a thread, which attaches to fixed substances, such as rocks or weeds. Some appear to live on vegetables chiefly, but the greater number are rapacious of animal sub stances in the extreme. They seize, in deed, whatever they find, with the most violent avidity, following in the wakes of ships, for the sake of nearly every thing thrown from them, and arc fatal to those mariners who slip from their hold on the rigging into the sea, in which case the sharks are seen to tear them to pieces, with all the violence of competition. They are in most instances solitary wan derers through the ocean, but in some species are gregarious. They contain large quantities of oil, and their skin is convertible to several useful purposes.
There are thirty-four species. The fol lowing are the most entitled to attention. S. carcharios, or the white shark, attains sometimes the length of thirty feet, and is the most fierce and rapacious inhabi tant of the ocean, in the depths of u Inch, particularly in the warmer latitudes, it principal], ranges. According to some writers, a man, and even a horse, has been found entire in the body of one of these animals ; and the teeth of this, or some larger species, are exhibited in the British Museum, four inches and a half in depth. The intestines of this animal generally contain a vast number of tape worms, which may account, in some de gree, for its peculiar voracity.
S. maximus, or the barking shark, is about the size of the former, and is of ten seen near the Hebrides in small shoals of six or eight, but generally in single pairs. These have nothing of the
fierceness of the former species, and will suffer themselves to be handled without resistance. They subsist on sea-weeds, and their stomachs have never exhibited indications, on being opened, of any other substances. They often sport about the billows with great agility and appearance of delight, and will suffer a boat to ap proach them so nearly, that the har pooner may pierce them with the instru ment in his hand. But it is stated that the wounds thus inflicted often excite at first no symptom of pain, and that in some cases no appearance of this is in dicated, till the combined efforts of two men have urged the instrument to its fullest depth, when they exhibit extreme agitation and rapidity, traversing the wa ter with the most turbulent movements, and summoning into exercise, for many Lours, all the skill and energy of those engaged in this critical pursuit. See Pis ces, Plate VI. fig. 1.
S. glaucus, or the blue shark, is the most elegantly shaped and coloured of all the species, is about ten feet long, and found in almost every sea. In the season for pilchards it abounds on the coast of Cornwall, and is often taken with large hooks.
S. stellaris, or the greater spotted dog fish, is a native of the seas of Europe. It seldom exceeds in length six feet. Its snout is considerably elongated, whence it derives its designation of the dog fish. It is found chiefly in rocky situations, and preys upon various shell-fish. It pro duces nineteen at a birth but does not appear extremely abundant. Its flesh is eaten, and its skin is an article of com merce.
S. zygana or, the hammer-headed shark, is sixteen feet long, and inhabits the Mediterranean and Indian seas, where its depredations are incessant and most formidable. It is distinguished by its head being dilated on the sides to an extraordinary extent, and by the eyes be ing at the extremities of these sides.
S. ss(tiatina, or the angel fish, is distin guished by a large and flat head, round ed in front, is found in the European seas, and grows to the length of seven feet. It is highly fierce and formidable.