Campanularians.
All the Campanularians, of which Oceania ([Fig. 68]), Clytia (Fig. 73), and Eucope ([Fig. 61]) form a part, belong among those little shrub-like communities of animals called Hydroids, from which most of our Jelly-fishes are developed. They differ in one essential feature from the Tubularians. ([Fig. 93.]) The whole stem, from summit to base, is enveloped in a horny sheath, extending around both the fertile and sterile individuals of the community, and forming a network at the base of the stem, which serves as a kind of foundation for the whole stock. To the naked eye such a community looks like a tiny shrub (see [Fig. 57]), with the branches growing in regular alternation on either side of the stems. The reproductive calycles, i.e. the protecting envelopes covering the young Medusæ, usually arise in the angles of the branches formed by a prolongation of the sheath. These calycles or bells, as they are called, assume a great variety of shapes,—elliptical, round, pear-shaped, or ringed like the Clytia. ([Fig. 72.]) In one such bell there may be no less than twenty or thirty Medusæ developed one below the other; when ready to hatch, the calycle bursts and allows them to escape.
Eucope. (Eucope diaphana Ag.)
In Figs. [60] and [61] we have a representation of our little Eucope, one of the prettiest of the Jelly-fishes belonging to this group; [Fig. 57] represents the Hydroid from which it arises; a single branch with the reproductive bell being magnified in [Fig.58]. In [Fig. 59] is seen a portion of the Jelly-fish disk, with the fringe of tentacles highly magnified. The disk of the Eucope ([Fig. 60]) looks like a shallow bell, of which the proboscis often seems to form the handle; for the disk has such an extraordinary thinness that it turns inside out with the greatest ease, so that the inner surface may become at any moment the outer one, with the proboscis projecting from it, as in [Fig. 60], while the next movement of the animal may reverse its whole position, and the proboscis then hangs down from the inside, as in other Jelly-fishes. (See [Fig. 61].)