Page:The American Cyclopædia (1879) Volume XIV.djvu/852

 826 SHAKJA SHARK in a dry box, and are very soon killed by fresh water. It is a matter of considerable physio- logical interest to ascertain how this fish is en- abled to live so long a time out of water ; it has no air bladder or rudimentary lung for the aera- tion of the blood ; it is not known to have any special arrangement of the gills or accessory sac for retaining water ; the gill openings are very large, just the opposite from the case in the eels and other fishes which live long out of water, and would permit the gills to become very soon dry and improper to circulate the blood. It must be remembered that the body is soft and scaleless; cutaneous respiration is very important in batrachians, and perhaps the necessary oxygenation of the blood is effected through the skin, as in the synbranchtu of Suri- nam, when the gills are not in action, under the control of the par vagum nerve ; perhaps also air may be swallowed, and intestinal respiration supply the necessary oxygen, as in cdbitit. The gill openings, though large, may be accu- rately shut, and the bulging cheeks may t Im- retain sufficient water to prevent the desicca- tion of the gills, assisted probably by the skin as a respiratory organ. The radiated shanny (P. subbifurcatus, Storer), found rarely on the coasts of Massachusetts and New York, is about 5 in. long, reddish brown above and yellow- ish white below, with three dark-colored bands passing backward from the eyes; the lateral line is subbifurcated, and there are filaments on the nostrils. SIIIRJA, a seaport town of Oman, Arabia, capital of a province of the same name, on the Persian gulf, in lat. 25 20' N., Ion. 65 36' E., 215 m. N. W. of Muscat; pop. about 25,000. It has a wall on the land side, but is open toward the harbor, which is a narrow creek run- ning parallel with the coast, and deep enough for only small vessels. It has a large market place in the S. end, in the middle of which is the government treasury, a stone building strongly guarded. The shops are well built, and display Indian and Persian goods, and the manufactures of the place, principally red cloaks, carpets, curtains, arms, and filigree jewelry. A large part of the population are weavers, who occupy the N. quarter. Sharja is the principal port through which are im- ported the goods of Persia, and it is the chief place on the coast for the sale of cotton, wool, the metals, asses, and dromedaries. It has a large trade, and but for its inferior harbor it would be a place of much commercial impor- tance. It is virtually independent. SHARK, an extensive family of marine car- tilaginous fishes, with the rays or skates and the chimrara or sen cat forming the order of plagiostotnes or selachians, elevated under the latter name to a class by Agassiz. The sharks may be distinguished from the rays by their elongated fusiform body, branchial apertures on the sides of the neck, pectoral fins of the usual form and situation, and large, fleshy, and powerful tail, which is the principal organ of locomotion; the nose is pointed and projects beyond the mouth, which is large and armed with formidable cutting teeth in several rows; the upper surface of the head often presents a pair of respiratory spiracles; the eyelids are distinct, with a free margin, and many have a nictitating membrane ; the cartilaginous scapu- lar arch is not attached to the spinal column, which contains more ossific matter than the other parts of the skeleton ; the gills have their margins attached, the water escaping by five branchial openings (sometimes more) ; the skin is rough with osseous tubercles ; the aortic bulb has several series of valves, and the shortness of the intestine is counterbalanced by an ex- tended spiral valve. They are essentially car- nivorous, and, as in the birds of prey, the fe- males are larger and fiercer than the males; they swim with great ease and rapidity, play- ing around the fastest ships and steamers; they devour either living or dead animal matters, but, from the situation of the mouth on the under side of the head, are obliged to turn on the side or back to seize a large object. Many of the smaller species have received the names of dog and hound, with various canine epithets, from their habit of following their prey in packs. Sharks are higher than ordinary fish- es in the phenomena of reproduction; there is with them true sexual union, and they are ovo viviparous, that is, the eggs are hatched in the oviducts, though they are often expelled before the embryo has quitted them ; the egg presents in its early development many pecu- liarities of those of the higher vertebrates. In some the eggs are received into the villous oviduct, in which as in a uterus the young are developed ; under these circumstances ova are observed in different stages of development, and frequently one in each oviduct. In oth- ers the egg is received in a horny, semi-trans- parent, oblong case, with long convoluted ten- drils at each corner, deposited near the shore in the winter months, and moored by the ten- drila ; the case has an elongated fissure at each end for the entrance and exit of water; the young animal swims about for a time, deriving its nourishment from the attached yolk bag. The egg cases are often cast ashore by the waves, and are commonly known as sailors' purses. About 100 species of sharks are known, mostly in northern waters and the eastern hemisphere ; some are almost cosmopolite, while others have a limited geographical distribution; the family contains the largest of the fishes, the great basking shark attaining a length of more than 80 ft. In the family scylliidce, generally called dog fishes to distinguish them from the sharks proper, spiracles are present ; the snout is short and blunt; the gill openings are five, the last one over the base of the pectoral; two dorsals, far back and behind the ven- trals ; an anal present ; caudal long, truncated at the end, with a notch on the under side ; no caudal pit ; a furrow at the corners of the mouth ; teeth with a pointed median cusp, and