SHARK 829 small, with radiating curved points, so that the skin feels rough ; the eyes are very small. The great basking shark (S. maximus, Ouv.) is the largest of this .class of fishes, attaining a length of 30 or 40 ft., and even over 60 ft., if the shark stranded at Stronsay in 1808, and Great Basking Shark (Selachus maximus). described as the sea serpent, belonged to this species. It descends in summer from the neighborhood of Greenland and Spitzbergen to the English channel and the middle United States. Notwithstanding its size and strength, it is the least ferocious of the sharks ; it does not appear to feed on fishes, but on cuttle fishes, crustaceans, medusae, and echini, and, according to Pennant, also on sea weeds. It is sluggish, and fond of reposing at the surface in the sun with the dorsal raised in the air, and hence called sun fish, sail fish, and bask- ing shark ; under these circumstances it is easily approached and harpooned ; this is often done for the sake of the oil of the liver, which amounts to several barrels in a full-grown fish ; from its speed and strength it is apt to pull a boat under water or overturn it ; it has been known to drag a vessel of 70 tons against a fresh gale, and requires often 24 hours to fatigue and kill it. It is dark slate-colored above, and lighter below. The S. elephas (Le- sueur) is probably the same species; it has been taken in the bay of Fundy 40 ft. long ; on the New England coast it is called the bone shark by fishermen. In the family alopeciida the snout is short and conical, the spiracles and nostrils very small, the gill openings small, the last one over the pectorals ; mouth com- paratively small, the teeth not serrated, trian- gular, sharp, and alike in both jaws ; no tooth on the mesial line, and a crescentic fold of skin behind the upper teeth ; the second dorsal Sea Fox (Alopias vulpes). opposite the anal and very small; pectorals large and triangular; upper lobe of tail as long as the body, with a pit at the root ; scales small and three-pronged, and intestinal valve spiral. It contains the single genus alopias (Raf.), and the single species A. vulpe* (Raf.), the sea fox, swingle-tail, or thresher shark; it attains a length of 15 ft., but is generally much smaller than this ; the body is fusiform, bluish lead-colored above, white below, with light blue blotches on the outer edge of the abdomen. It attacks its prey and enemies and defends itself by blows of the tail ; the food consists principally of herring, mackerel, and other surface and shoal fish. It is found in the European seas from the Mediterranean to the coast of England, and also on the Amer- ican side from the British provinces to the middle states ; it has been known to attack fishing boats in the bay of Fundy. In the family cestraciontida the nostrils are slit to within the mouth, which is at the fore end of the snout ; the spiracles are rather behind the eyes ; the gill openings small, the last one above the pectorals ; a spine forming the front of each dorsal ; tail short and wide, strongly notched below ; teeth pavement-like, in round- ed oblique scrolls ; the body short and stout, head large, and eyes prominent. The genus cestracion (Cuv.) furnishes the only living rep- resentative of a family numerous in the sec- ondary geological epoch ; the C. Phillipsii (Cuv.) is 2 or 3 ft. long, brownish above and whitish below ; it inhabits the Pacific from Australia to Japan ; it is called nurse in Aus- tralia, and cat or kitten shark in China ; the young are often seen in Canton insect boxes. In the family scymnidce the dorsals are with- out spines, and there is no anal nor nictitating membrane ; the upper teeth are pointed, the lower broader and cutting and not denticula- ted ; no tail pits ; intestinal valve spiral. In the genus scymnus (Cuv.) the spiracles are far behind the eyes, the gill openings small, the body short and thick, and the lobes of the tail not very unequal. The Greenland shark (S. lorealis, Flem.) attains a length of about 14 ft., and is ashy gray ; it inhabits the arctic seas, sometimes visiting the northern shores of Eu- rope and America. It attacks whales fiercely, and scoops out at every bite a piece as large as a man's head, the mouth being 20 to 24 in. wide. According to Scoresby, they generally attend the cutting up of whales, helping them- selves freely to blubber; the men often fall into the water among them, but are not at- tacked ; they are so tenacious of life, and so insensible to wounds, that they will return to their prey after receiving lance stabs which would kill any other shark ; the muscles, es- pecially those of the jaws, retain their irrita- bility for several hours after death ; the heart is said to be very small, and its pulsations only six or eight in a minute, which would explain their tenacity of life and the difficulty of reach- in? any vital organ. They also eat small fishes and crustaceans. They are liable to the attacks of a parasitic crustacean (lerruea elongata, Grant), 2 or 3 in. long, which fixes itself so often to the cornea of the eyes, that it was formerly supposed to be a natural appendage; this sometimes makes them apparently blind.
