Each of the little creatures has a tubular stalk which passes through the hole at the base of the cup, and is continuous with a tube of gelatinous material in the interior of the horny stem, and thus each member of the colony is directly connected with all the others, so that any nutrient matter collected and digested by one member may be absorbed into the central tube for the nourishment of the entire company of little socialists, the activity of the one being thus made to compensate for the laziness or incompetency of others. And this provision seems to be absolutely necessary for the well-being of the colony as a whole, for a close examination will often show that a kind of division of labour has been established, since it includes two or three distinct kinds of polypites, each adapted for the performance of a certain function. Thus, in addition to the feeding or nutritive members of the community, there are some mouthless individuals whose sole function seems to be the production of eggs for the propagation of the species, while others, also mouthless, develop an enormous number of stinging cells, probably for the protection of the whole community against its enemies, and these must therefore be provided, as we have seen they are, with a means by which they may derive nourishment through the agency of the feeding polypites. [Illustration: FIG. 82.--_Tubularia indivisa_] [Illustration: FIG. 83.--THE BOTTLE BRUSH (_Thuiaria thuja_)] When the eggs are liberated from what we may call the reproductive members, they are carried away by the currents or tides, and soon develop into little _larvæ_ which are very unlike the parent, since they are covered with minute vibratile cilia by means of which they can swim freely. This they do for a period, and then settle down, lose their cilia, become stalked, and thus constitute the foundation of a new colony. A tubular stalk grows upward from its root, new members are added as outgrowths or buds from their progenitor, and so the growth proceeds until an extensive colony of hundreds of individuals has been formed. We have spoken of the hydroid communities as being washed up on the beaches of our rocky coasts, but the collector of these interesting objects should not depend on such specimens for purposes of study. It is undoubtedly true that splendid examples of the sea firs and their allies are frequently washed up by the waves, including some species that inhabit deep water, and which are, consequently, not to be found by the ordinary collector in their proper habitat, and that these may often be secured with the polypites still alive; but several species are to be obtained between the tide-marks, especially at extreme low water, growing on rocks, weeds, and shells; and we have often met with good specimens, still alive, attached to the shells of whelks, scallops, &c., in fishmongers’ stores, even in inland towns. [Illustration: FIG. 84.--_Antennularia antennia_]