. Cassell's natural history. Animals; Animal behavior. glO NATURAL EISTOET. other, and separated by a kind of semi-tubular and cellular tissue, which forms layers of considerable extent. Usually the number of tubes is small at the base of a mass, and it increases at each layer of the cellular tissue, so that it is very great at the surface of a large piece. Each tube is made up of a number of sclerites, nearly united together, so that their original shape cannot be made out, and it is hollow witliin, and more or less cyliiidrioal. But there are funnel-shaped {Drojections inside, and als
. Cassell's natural history. Animals; Animal behavior. glO NATURAL EISTOET. other, and separated by a kind of semi-tubular and cellular tissue, which forms layers of considerable extent. Usually the number of tubes is small at the base of a mass, and it increases at each layer of the cellular tissue, so that it is very great at the surface of a large piece. Each tube is made up of a number of sclerites, nearly united together, so that their original shape cannot be made out, and it is hollow witliin, and more or less cyliiidrioal. But there are funnel-shaped {Drojections inside, and also incomplete horizontal tabulaj. There are no septa. The tubes are separate, slightly porose, and the new ones spring from the horizontal layers, whose cavities communicate with the larger tubes. The JJolype fills the upper jjart of the tube, and its outer derm passes over the edge, or rather is continuous with it, and the sclerites are developed in its midst. There are eight tentacles, with from fifteen to seventeen pinnae on either side of each, and there are spicules within. The mouth has a slightly raised lip. When the polype is alarmed, the tentacles close, and then the whole is with- drawn into the tube. The lower part of the tube, above the uppermost tabula, is occupied by the gastric cavity, separated above from the stomach by a delicate tissue. The ovaries are in the lower cavity, and the mesenteries, eight in number, are like thin slender cords. The genus Tuljipora forms a sub-family of the Alcyonidte, and there are several sjiecies of J it. Probably it is of great antiquity, for there are things like it in the Devonian i-ocks. The Alcyoninse are fleshy and soft, and increase by ova, and also in mass by a process of budding from the sides of the polypes. The buds are enclosed in a very strongly- developed coenosarc, and the mass may be simple, lobed, or branched. There are two divisions of the sub-family. In the armed or spiculate one, the tissue of the body' is thin
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