the stickle-back, in ichthyology, a genus of fishes belonging to the order of thoracici. There are three rays in the membrane of the gills; the body is carinated; and there are some distinct prickles before the back-fin. There are 11 species distinguished by the number of prickles on the back. One of these species, the aculeatus, stickleback, bartlefish, or sharpling, is common in many of the British rivers. In the fens of Lincolnshire, and some rivers that proceed from them, they are found in prodigious quantities. At Spalding there are once in seven or eight years amazing shoals that appear in the Wolds, and come up the river in form of a vast column. They are supposed to be the multitudes that have been washed out of the fens by the floods of several years, and collected in some deep hole, till overcharged with numbers, they are periodically obliged to attempt a change of place. The quantity is so great, that they are used to manure the land, and trials have been made to get oil from them. A notion may be had of this vast shoal, by being informed, that a man being employed by the farmer to take them, has got for a considerable time four shillings a-day by selling them for a half-penny per bushel.—This species seldom reaches the length of two inches; it hath three sharp spines on the back, that can be raised or depressed at pleasure. The colour of the back and sides is an olive-green; the belly white; but in some the lower jaws and belly are of a bright crimson.