occasionally seen stranded on the coast, were produced; but there are some whose planulas do not settle down, but are always free swimmers, and they divide into Medusæ in the sea. This intensely interesting course of life is modified in all the hundreds of kinds of creatures which are connected with the jelly-fish in classification, by their having many structures in common. The creatures thus classified with the jelly-fish are called Hydrozoa, or Water Animals, and they pass two lives, one of which is commonly observed on the seashore everywhere. One life is a fixed one, and the other is a free swimming one; in one stage it is eating and drinking, and in the other, these functions are not always or often carried out. The egg-laying and perpetuation of the animal are the duty of the greater part of the beautiful branched and hair-like things which are arranged by visitors to the seaside in patterns, and retained as memorials of pleasant days, and which are popularly called sea-weeds. They are not such things, but are the delicate stems, branches, and bud-like homes of the parents of tiny jelly-fish, which are only to be caught in the open sea. These horny stems and branches end in creatures with tentacles or feelers, and they live between tides, in rock pools, and at low water. Sometimes these fragile, plant-looking things are fixed on to stones or sea-weed, and some get a ride by growing on shells, inhabited, since the death of their original possessor, by the Hermit Crab. One very numerous tribe of these feathery-looking weeds, but which are truly animals, is common everywhere on the shore, between tide-marks into deep water. Their stems are branching, and the little bud-like things on them, when watched in still water, may be seen to put forth pretty colored bodies with tentacles around a centre; and as there may be hundreds of them on the branches and stem, the creature resembles a bunch of rayed flowers. Hence the name Sertularia, from sertula, a small garland.