As its name imports, the stone-lily or encrinite had a plant-like form. It consisted of a long stalk fixed by the lower end to the sea-bottom, and supporting above a lily-shaped cup, in which were placed the mouth and stomach (Fig. 19 _a_). The stalk consisted of circular plates (some of them not so thick as a sixpence), having their flat sides covered with a set of minute ribs radiating from the centre, and so arranged that the prominent lines of one joint fitted into corresponding depressed lines of the adhering ones. The centre of each joint was pierced by a small aperture, like the axle of a wheel, which, when the stem was entire, formed part of the long tube or canal that traversed the centre of the stem, and served to convey aliment to the remotest part of the animal. Detached joints have thus a wheel-like appearance (Fig 19 _c_), and hence their common name of wheel-stones. In many species they were not all of the same diameter, but alternately larger and smaller, as if the stem had been made up of a tall pile of sixpences and threepenny pieces in alternate succession. This variation gives a remarkably elegant contour to the stalk. The flower-shaped cup consisted of a cavity formed of geometric calcareous plates, and fringed along its upper margin with thick calcareous arms, five or ten in number, that subdivided into still more slender branches, which were fringed along their inner side with minute _cirri_ or feelers. All these subdivisions, however fine, were made up of calcareous joints like the stalk, so that every stone-lily consisted of many thousand pieces, each perfect in its organization and delicate in its sculpturing. One species peculiar to the Liassic formation (_Extracrinus Briareus_) has been calculated to contain one hundred and fifty thousand joints! The effect of this minute subdivision was to impart the most perfect flexibility to even the smallest pinnule. The flower could instantly collapse, and thus the animals on which the encrinite preyed were seized and hurried to the central mouth. The lower part of the cup, or _pelvis_, as it is called, contained the stomach and other viscera, and communicated with the most distant part of the body by the central alimentary canal.