SERPENTINE 347 SERRANTTS are opposed so as to convert it into a canal — hence the fangs are said to be canaliculated. This canal opens by a wide aperture above into the poison gland, so that by the compression, muscular and friable, of the gland, the poison flows down the canal and is ejected, through the lower minute aperture, into the wound made by the fang. The poison of different serpents varies in intensity and virulence, but appears to take effect on the blood. The most effective treatment for snake-bite is to tie a ligature tightly round the limb, above the wound, and to excise the part freely, and then to suck the blood re- peatedly, and cauterize the parts deeply before removing the ligature. In suck- ing a poisoned wound, the danger con- sists in there being a crack or wound in the mouth by which the poison may be absorbed. The digestive system of serpents pre- sents nothing worthy of special remark, save that the intestine ends in a cloaca opening transversely. There is no urinary bladder, and the heart (as in all reptiles save the Crocodilia) is three-chambered. Serpents are divided into three groups: innocuous, venomous colubrine, and viper- ine, the last two groups possessing poi- son fangs, the boas, which kill their prey by constriction, belonging to the first. Broadly speaking, the innocuous sei'pents are oviparous, the venomous are ovovivi- parous. Most of the former deposit the eggs in a long string in some heap of decaying vegetable matter, and leave them; while some of the larger serpents coil round their eggs, and hatch them by the heat o2 their bodies. Some of the innocuous kinds are capable of being tamed; the rat snake (Ptyas mucosus) is often kept in houses in India for the purpose of destroying rats and mice. SERPENTINE, rra abundant mineral occurring in one or other of its numerous varieties in all parts of the world. Crys- tallization, probably orthorhombic, but when found in distinct crystals always pseudo-morphous. Occurs usually mas- sive, but sometimes fibrous, foliated, fine granular to cryptocrystalline. Color shows many shades of green, yellow; streak, white, shining; translucent to opaque; feel, greasy; fracture, either con- choidal or splintery. Composition: Silica, 44.14; magnesia, 42.97; water, 12.89= 100, corresponding with the usually-ac- cepted formula, 2MgOSi0 2 -f MgO,2HO. In petrology, a rock, consisting essen- tially of a hydrated silicate of magnesia, resulting from the alteration of magne- sian rocks, of all geological ages, espe- cially those of olivine. It contains also some protoxide of iron, and other impuri- ties which cause a great variation in color, which is often of a dull green, but is also marbled and mottled with red and purple. _ It takes a high polish, and is turned into ornamental articles. The ac- cessory minerals are numerous, the most frequent being pyrope, bronzite, magne- tite, and chromite. In geology, serpen- tine is considered an altered intrusive rock, originally a trap or dolerite with olivine. SERPUKOFF, an ancient Russian town, 57 miles by rail S. of Moscow, on the Nara, 3 miles from its confluence with the Oka. It contains a cathedral (1380), and was before the World War, a place of considerable commercial and industrial importance, manufacturing chiefly cot- tons, woolens, leather, paper, furniture, and earthenware. Pop. about 31,000. It was formerly a fortress protecting Mos- cow on the S. SERPULA, a genus and family of Annelidse, whose organs of respiration are in tufts attached to the head and anterior part of the body. In most cases, they live in tubes, and hence are often called tubicolse. In some the tubes are calca- reous, in others horny, the result of tran- sudation; others, still, are formed of grains of sand, or other particles, bound together by a membrane, also transuded. The genus serpula has the anterior por- tion spread out in the form of a disk armed on each side with bundles of coarse hairs, and on each side of the mouth is a tuft of branchiae, shaped like a fan, and generally tinged with bright colors. At the base of each tuft is a fleshy filament, one of which is ever elongated, and ex- panded at its extremity into a disk, which serves as an operculum, and seals up the opening to the tube, when the animal is withdrawn into it. The calcareous tubes of the Serpulse cover submarine bodies. SERRA DA ESTRELLA, a lofty range of granite mountains near the middle of Portugal, highest summit 6,460 feet. The range contains some remarkable lakes, part of which are tepid. SERRANTJS, sea perches; a genus of Percoidse; found on the shores of all tem- perate seas, and abound in the tropics, some of the latter species entering brack- ish and even fresh water, but all spawn in the sea. Body oblong, compressed, with small scales; teeth villiform, with distinct canines in each jaw, teeth on vomer and palatine bones; one dorsal, mostly with 9 or 11 spines, anal with 3. Two species, S. cabrilla, the smooth ser- ranus, and S. gigas, the dusky perch, are met with in the British Channel, and are common in the Mediterranean.
