Coming to the earthworms, which stand higher than the protozoa, though still very lowly, there seems little doubt that they are capable of forming and carrying out an intelligent purpose, since, when they pull leaves into their holes, they always catch hold of them by the proper part, so that they go down easily, and this they do even with the leaves of foreign trees, of which they can have had no previous experience. And if worms have experience, snails have both that and something better, or, at any rate, still more interesting to discover in a creature of this kind. “They appear,” says Darwin, “susceptible of some degree of permanent attachment. An accurate observer—Mr. Lonsdale—informs me that he placed a pair of land-snails, one of which was weakly, in a small and ill-provided garden. After a short time the strong and healthy individual disappeared, and was traced, by its track of slime, over a wall and into an adjoining well-stocked garden. Mr. Lonsdale concluded that it had deserted its sickly mate; but after an absence of twenty-four hours it returned, and, apparently, communicated the result of its successful exploration, for both then started along the same track, and disappeared over the wall.” Both snails and worms, however, stand higher in the scale than do the sea-anemones, amongst which latter creatures—those flowers of ocean, rivalling with their pillared stalks and many-coloured living petals the proudest ones on earth—we yet find an instance of what is called commensalism—the living together, that is to say, in friendly community of two separate and often widely sundered species, each thereby obtaining some benefit for itself. The other party to the arrangement is in this instance a crab—the hermit-crab—that curious anchorite which by living and moving about in the disused shell of another creature escapes the many dangers which would otherwise threaten its soft and palatable body. Indeed, the association may almost be said to be between three, rather than two, different species, each of them belonging to a separate and well-marked division of the animal kingdom—viz. to the mollusca, the crustacea, and the cœlentera respectively. As, however, the mollusc is represented by its house only, and not by itself—though, indeed, its house is structurally a part of it—it will be safest to consider the alliance as a dual rather than as a triple one. That the anemone establishes itself on the shell, not by mere chance, as might sometimes happen, did the crab allow of it, may be demonstrated in a very delightful way; for if, when it is attached to a stone, a hermit-crab should be placed in its vicinity, it will, after a time, abandon its post, and gliding, like a snail, to the hospitable portals of its friend’s domain, proceed to attach itself there, much to the satisfaction of the latter. For that the crab’s participation is of an active kind, that he does not merely not mind the anemone, and that the latter has