Page:Popular Science Monthly Volume 33.djvu/605

Rh elegant creature, with a bell like cut-glass, and long, waving tentacles. Its movements are so instinct with grace that an admirer of the lines and curves of Nature could desire no better or more fascinating occupation than the observation of an aquarium stocked with a few specimens of this attractive jelly-fish. The drawing is accurate, so far as mere shape goes, but no drawing can represent its jewel-like brilliancy or the elegance of its movements. Its chief interest to us, however, centers in its life-history, which is very different from that of Dysmorphosa. Its proper home is the deep water of mid-ocean, not the shallows near shore; and it has no attached stage of development, but floats or swims at all periods of its life. The eggs are thrown out into the water, and each one soon develops into the embryo which is shown, highly magnified, in Fig. 3.

This embryo, which is a planula adapted for floating instead of swimming, is a hollow sphere, the walls of which are formed of

 side view, and Fig. 8, a broad view of a young Liriope: b, swim-bell; d, stomach; e, mouth; f, larval tentacles; g, long tentacles of adult; h, short tentacles of adult; i, areas of adhesion; k, otocysts; l, radial canals.

two spherical shells, an outer one, a, which forms the surface of the body, and an inner one, c, which lines the central cavity, the two being separated from each other by a gelatinous layer, b, which serves to float the embryo in the water. The central cavity has at first no opening to the exterior, and the two shells are concentric, but they soon approach each other at a point, a', and