The animals belonging to this group, which may be characterised as _stelliform_ or star-like, are very abundant in every sea, and in several geological formations. They constitute many families, among which may be noted the MILLEPORINA of Ehrenberg, the polypidom of which Dr. Johnston describes as "calcareous, fixed, plant-like, branching or lobed, with cells scattered over the whole surface, distinct, sunk in little fosses, obscurely stellate, the lamellæ narrow and almost obsolete." (JOHNSTON'S _Zoophytes_, vol. i. p. 194.) In _Turbinolia_, the animal is simple, conical, striped, furrowed externally with larger and smaller ribs, the mouth surrounded by numerous tentacula, and solidified by a calcareous polypidom, which is free, conical, and also furrowed externally; attenuated at the base, but enlarged at the summit, and terminating in a shallow radiated lamellar cup or cell. Several species have been dredged off the coast of Cornwall, and the west coast of Scotland and Ireland. _T. melletiana_ is described as coral-white, wedge-shaped, somewhat compressed, with interspaces or ribs equidistant, smooth, and glossy. Above, the ribs turn over the edge, and are continued into the centre of the enlarged cup, forming its lamellæ. "That the zoophyte must have lived for some time after having become a movable thing, is proved," says Dr. Johnston, "by the ribs being continued beyond or round the point of attachment." The specimen here described was dredged alive, and Professor Forbes says of it that "it is a most interesting and beautiful species, the more so as it is certainly identical with Defrance's _Turbinolia melletiana_, found in both the crag formations." [Illustration: Fig. 66. Caryophillia cyathus (Lamarck).]