Page:The American Cyclopædia (1879) Volume XIV.djvu/854

 828 SHARK elegantly formed, and the most beautiful in color of the sharks, being fine slate-blue above and white below; the skin is granulated and rough. It is distributed in most parts of the globe, and is very bold and voracious ; its prin- cipal food consists of herring, shad, and oth- er migratory fishes ; it is a great pest to the British fishermen ; when hooked, if it cannot divide the line, it rolls over and over so as to wind it around the body, sometimes beyond the power of extrication except by the knife ; it also makes great havoc in the pilchard fish- ery, destroying the nets and devouring the fish. Like the white shark, this species is often at- tended by the pilot fish. (See PILOT FISH.) There are many stories of the affection of this species for its young, which are said to take refuge when alarmed in the stomach of the parent; there can be no doubt that small sharks are often found in the stomachs of the larger, but this is rather a proof of cannibalism than of parental affection. Of the American species of this genus may be mentioned the dusky shark (C. <>!>. nr>i*. Lesueur), attaining a length of 10 to 12 ft, dark brown above and dirty white below, occasionally found on tlie coast of the eastern and middle states ; the small blue shark (C. earuleua, Mitch.), 8 to 6 ft. long, slate- blue above and whitish below, found in the same waters; and At wood's shark (C. Atwoodi, Storer), coming nearest the great white shark, attaining a length of 13 or 14 ft., and a weight of 1,500 llis. The color of the last named is leaden gray above and white below ; it has been caught off the coast of Massachusetts. In the a/'iiniciil'i-, piked dog fishes, spiracles are present; the anal fins are wanting, and the dorsals, two in number, are each preceded by a strong spine. The genus acantfiias belongs to this family, and is described under DOG FISH. In the family galeidce, topes or hounds, the fins, nostrils, gill openings, and mouth are as in the carchariada ; there are very small spiracles ; the teeth are alike in both jaws, with cutting edges and u cusp pointing obliquely outward ; the upper lobe of the tail is much the longer and notched near the end ; the scales small, three-ridged, with a median cusp. In the genus galeut (Guv.) the pupil is round above and angular below ; the teeth smooth on the inner edge, serrated on the outer, with the cusp smooth ; the median teeth straight, jagged at the base on each side ; no tail pits, and the intestinal valve spiral. The common tope or penny dog (0. vulgarit, Cuv.) attains a length of 6 ft. ; the body is fusiform, slate- gray above and grayish white below ; it is less rapacious than the blue shark, and is a pest to the fishermen in summer on the southern coasts of England ; when hooked, if it cannot bite off the line, it rolls itself up in it; the young, to the number of 30 or more, are born in May and June ; the liver is of some value for its oil. The genus muttelu* (Artedi) of this family has been described under DOG FISH; in this the teeth are pavement-like as in the rays. In the family lamnida the gill openings are very large, all anterior to the pectorals ; they have no nictitating membrane, and the spira- cles are small, tail pits evident, caudal broadly forked and nearly crescentic, tail keeled on the sides, and the intestinal valve spiral. In the genus lamna (Cuv.) the snout is a three- sided pyramid with a short nasal fiap, the spi- racles far behind the eyes, and the mouth wide ; the teeth are triangular, not serrated, with an acute toothlet at the base on each side, the surface resting on the jaw being deeply con- cave ; there is a vacant space above and below instead of mesial teeth ; skin comparatively smooth, and the scales very small. The por- beagle shark (L. cornubica, Cuv.), found on the northern coasts of Europe especially in autumn, attains a length of 9 ft. ; it is uniform grayish black above and white below. They associate in small packs, from which and the porpoise-like form of the body the common name is derived ; they feed chiefly on fishes and cephalopods ; they are ovoviviparous. The mackerel shark (L. [oxyrhina]punctata, Mitch.) of North America is greenish on the back, lighter on the sides, and white below ; the teeth are narrow, long and nail-like, calculated for holding rather than cutting prey ; the head Mackerel Shark (Ltunna punctata). and sides are punctured by a series of mucous pores. Like the English porbeagle, this spe- cies from its size and formidable teeth is the most dangerous of the common sharks, though it is not known to attack man unless in self- defence ; it is common in summer on the New England coasts, and is a great pest to the mack- erel and cod fishers ; it may attain the length of 10 ft., but is usually not more than half this; it received its name from its following the shoals of mackerel on which it feeds ; the liver is valuable for oil, a single fish often yielding six or seven gallons ; though generally used by curriers only, when made carefully from fresh livers it is as good as whale oil to burn. The gray shark (odontaspis griseus, Ag.) has the fore teeth simple, long, conical, with smooth edges and one or more basal toothlets; toward the corners the teeth are smaller and more incisorial ; it attains a length of 4 to 7 ft., and is light bluish gray above, lighter on the sides, and white below ; it is not uncommon in Long Island sound, and of late years in Massachusetts bay. In the genus selachus (Cuv.) the snout is short and blunt, and the gill openings almost meet under the throat ; the teeth are very small and numerous, conical, without serrations, curving backward, and without toothlets and notches ; scales