Page:The American Cyclopædia (1879) Volume XV.djvu/137

 SNAIL SNAKE RIVER 129 they have no operculurn, the opening during hibernation being closed by a secretion from the mantle, which hardens into what is called the epiphragm ; the shell is generally turned from left to right, the free edge to the right, but they are often reversed ; the newly hatched young resemble their parents, and have a shell of one whorl and a half. They are sensitive to cold, and like moist places; the sense of touch is acute, especially in the tentacles, and they appear to have a sense of smell ; they are nocturnal, and feed principally on plants, though sometimes devouring each other. The repro- ductive season is toward the end of spring; the eggs, to the number of 30 to 100, are de- Sosited in moist places, in natural or artificial oles ; the young come out in 20 to 30 days. Snails are distributed very widely, from the northern limit of trees to Tierra del Fuego, from the hot and moist plains to a height of 11,000 ft. on mountains; some are cosmopo- lite, ranging wherever their food is found, and others are restricted within narrow limits. About 1,500 species have been described, some of which from their voracity are very injurious to vegetation, and some useful to man as food ; they are very tenacious of life, and able to re- sist long droughts. A specimen of the desert snail of Egypt (helix desertorum), which re- mained dormant in the British museum four years, afterward lived in the possession of one of the curators more than two years. The genus helix (Lam.) is the type of the family. The Eoman or vineyard snail (H. pomatia, Linn.) is a large species, reddish brown with paler bands ; these snails were used as food by the ancient Romans, who reared them in parks, and fattened them on cooked meat and flour, obtaining them from the islands of the Medi- terranean ; they are still eaten in many coun- tries of Europe, especially by Roman Catholics during Lent, being considered as fish; great numbers are eaten in France; they are also recommended as an ingredient in soups for con- sumptive persons. The reproductive internal organs, in the apex of the shell, consist of many parallel cooca, each of which has an external layer producing eggs, and an internal sac pro- ducing semen ; the apparatus is very complex. The H. aspersa (Linn.), or common garden snail, originally from Europe, but now natu- ralized in most parts of the globe, is also used as food, when boiled in milk, for consumptives. These species when abundant are very destruc- tive, laying waste whole gardens in a single night, always attacking the tenderest and most succulent plants ; besides their natural ene- mies, mammals and birds, great numbers are killed by fires, inundations, sudden changes of temperature, felling of forests, cultivation of the land, and by hogs and poultry following the plough ; the remedies for their depreda- tions are the same as for the slugs. The largest of the American snails is the H. albolabris (Say), of a yellowish horn color, with white, broadly reflected lip ; the shell has five or six whorls, with minute revolving lines and the umbilicus closed ; in October they cease feed- ing, and select a place under some log or stone, where they fix themselves for the winter, American Snail (Helix albolabris). mouth upward. For details on the American species, see Dr. A. Binney's "Terrestrial Air- breathing Mollusks of the United States" (3 vols., Boston, 1851, and vol. iv., a continuation by G. W. Binney, Boston, 1859). SNAKE. See SERPENT. SNARE BIRD. See DARTER. SNAKE RIVER (also called Lewis fork or river, Saptin river, and Shoshone river), a tributary of the Columbia, rising in the Rocky mountains in N. W. Wyoming, near the sources of the Yellowstone and Madison rivers, at an elevation of about 8,000 ft. above the sea, about lat. 44 K, Ion. 110 80' W. It flows N. W. to the junction of Lewis fork, the out- let of Shoshone and Lewis lakes ; then S., ex- panding in its course into Jackson lake, and again N. W. to the junction of Henry's fork (a total course of nearly 200 m.) in Idaho, about lat. 43 15', Ion. 112. Henry's fork rises in Henry lake (6,443 ft. above the sea, about lat. 44 30', Ion. 111 30') in E. Idaho, on the border of Montana, near the head waters of Jefferson river, and has a S. course. From the junction the Snake describes a curve of more than 350 m. through S. Idaho, flowing S. W. and then N". W., and strikes the Oregon border in about lat. 44 40'; it then flows K about 200 m., separating Idaho from Oregon and Washington territory, when in about lat. 46 30' it turns W. into Washington, and after a further course of about 150 m. falls into the Columbia about 20 m. above the Oregon boundary, about lat. 46 15', Ion. 119. Its total length is upward of 900 m. Steamers ascend to Lewiston on the Idaho border ; navigation is then impeded for more than 100 m. by shallows and rapids, above which the river is again navigable for 150 or 200 m. In its course through S. Idaho, the Snake flows through a vast cafion, vary- ing in depth from 100 to 1,000 ft. ; many of its tributaries sink, and, passing under the strata of lava, fall from the sides of the cafion into the main stream; and here occur the American, Shoshone, and Salmon falls, for an account of which see IDAHO, vol. ix., p. 167. Its chief tributaries on the right bank are the Malade from the north; the Boise", Payette, Weiser, Salmon, and Clearwater (which enters at the point where the Snake leaves the Idaho boundary) from the east ; and the Palouse (in