HAIRS, in botany, are very different from the hair of animals, although there is sometimes a considerable general resemblance, and the same purpose of protection from cold and from various atmospheric influences seems also to be sometimes served by them. They are produced by no special organ analogous to the bulbs from which the hairs of animals grow, but are composed of cellular tissue, arise from the epidermis, and are covered with extensions of the cuticle. Some hairs consist of a single elongated cell; some of several cells placed end to end. The gradations are quite indefinite between the most elongated hairs and the mere warts or rugosities which often appear on the surface of plants. In like manner, hairs pass into bristles (seta) and prickles (aculei), which are merely stronger and harder hairs; but spines or thorns are totally different, arising from the wood of the stem or branch. Hairs are very often connected with glands, which are cells or clusters of cells, producing secretions; hairs often arise from glands, and then generally serve as ducts through -which the secretion may pass: but hairs also often bear glands at their apex. Stinging hairs, as in nettles, loam% and
some malpighias (see these heads), are ducts, with venom-secreting glands at their base.
Trichiurus, a genus of acanthopterous fishes, which, on account of oeir compressed and very elongated form, have been classed in the ribbon-fish family, tut are otherwise allied to the mackerel, tunny, etc., and are therefore, in recent sys ematic works, referred to the family scomberidm The dorsal fin extends along the thole back. and is spiny throughout; there are no ventral fins, no anal fin, and no tail dn, the tail ending in a single elongated filament. One species, the SILVERY HAIR-TAIL lepturus), sometimes called the blade-fish, is found in the Atlantic ocean, and has seen cast on the shores of Britain, but is more common in warmer regions. It is called .aber-fish in Cuba. It sometimes attains a length of 12 feet. Its flesh is good.—An East Indian species, the SAV.4LA (T. cacala), is much eLteemed for food, and commonly sold in the markets of India.