many animals should not be put in one and we took it on account of the odd apbottle; and that considerable care is need-pearance of its tufts of sea-weeds. ed in planning for the inmates of a small aquarium, lest some should be too large or too voracious, and thus overpower the others; so we began to consider whether we should take any of the crabs which were running in awkward sidelong motions over the sand, or which dropped out from among the large olive-brown seaweeds when we lifted them. I had my doubts whether they were fitted for a general aquarium, and whether they did not require a vase of water to themselves, but we thought we would give them a trial. Some little harbor or shore crabs (Carcinus maenas) looked rather inviting; for although when full grown, as we see them carried in baskets for sale, they are of a dark unpleasing green color, yet they are somewhat prettier when young, and their thin shelly coats are mottled over with white. We found them of all sizes and in great numbers in the pools among the rocks, where the last high tide had left them. We had read of their strange transformations, and how, in the earlier periods of their existence, they are so unlike the fully developed crab, that they were long believd to be distinct animals, and had received scientific names from naturalists, who never suspected that they were crabs at all; and no one who saw the figures of these creatures, which Professor Bell has given in his work on the Stalk-eyed Crustaceans" in their different conditions, would wonder at this mistake. Then the singular renewal of the crust which incloses the crab, and which is cast off as he grows older, and needs a larger one, offered an inviting subject for examination. Charlie and I had read of these things, and consequently felt much interest in the whole race of crabs, so we resolved to venture on admitting a small long-legged spider-crab. This animal could scarcely be called handsome, for it so much resembled a spider that few would care to touch it. It was about the size of a large garden spider, having a triangular body, with long slender legs, which were very rough and hairy, and large eyes. It moved about among the rocks very slowly, and was covered with a complete little forest of sea-weeds and corallines which grew on its back and legs. A small harbor crab, too, in a similar condition, attracted us, 66 Assuredly no owner of a small aquarium, who wishes to have a "happy family," should invite into its circle any crab more than half an inch long; for not even those who have skill to bring together the raven and the dove in seeming peace, could contrive to subdue the voracity, or to soften the tempers, of these dwellers by the sea. Notwithstanding the experience of the writer of this paper, he determined on possessing some very small hermit crabs. This creature is compared to the hermit because it dwells in a solitary cavern as a hermit might do. But another of its names, the soldier crab, is equally expressive, for it is of a very unpeaceful nature. Little cares this crab how boldly he may have to fight, either in defense of house and home, or in attacking the empty castle which another of his kind may also covet. The peculiarity of all these hermit crabs consists in their having the body covered with a thin membrane instead of a calcareous crust, so that their tender bodies would be easily injured had not the Great Creator implanted in them the instinct which leads to their protection. When young, this crab ensconces itself in some periwinkle or other spiral shell, holding itself in by a strong tail, which is covered with a crust, and hanging its legs out at the opening of the shell. It soon outgrows its home, which it exchanges for another, and another, until finally the crab becomes so large that often nothing but a whelk shell will hold him. When a fresh shell is needed, he sets off in search for one, which he will fight for most zealously if it is contested by an enemy. Many naturalists believe, too, in the cannibal propensities of our hermit, and maintain that he eats his enemy; and, fierce and voracious as he evidently is, this ill report would seem not altogether unlikely. We had no difficulty in finding soldier crabs. There they were, from little creatures scarcely larger than a pea, to specimens which measured a full inch across. A touch of the claw hanging out of the shell caused it to be jerked in, where it became so firmly fixed as to resist all our endeavors to pull it out. Indeed, a large crab of this kind nipped us so fiercely when we made an attempt to do this, that we were glad that our fingers were en cased in gloves, and, notwithstanding this defense, we were quite conscious for some time after of having been nipped. Taking with us a few empty shells for their use, we carried some small ones away to our aquarium, where they seemed perfectly contented, and, for a while, quite harmless. One of them grew much faster than his neighbors, and we were amused one day by seeing him snatch most fiercely at a large shell. He next put his claw warily all round the inside, and, finding no obstacles, took possession of his castle, running rapidly into it as if he expected some one might deprive him of it. He remained there for more than an hour, but great was our surprise to see him after this time quite unsettled, and shortly making a fierce grasp at another shell. He was so embarrassed by his riches that one after another was tried and rejected. As the other crab remained quietly at home, no contest arose, and both now lived and grew quietly, through several changes of dwelling, till, in an evil hour, one of them nipped a hole in a favorite anemone. This served as a signal for dismissal, and Charlie carried them both off to a rocky basin, once more to become soldiers of fortune. It is not impossible that they shared the fate of some of their kind, for we saw boys around the pool gathering whelks and clamps for bait, and the crabs would scarcely escape their eager observation. Among the liveliest inhabitants of the sandy shallow waters, wo must reckon the shrimps. It is quite amusing to watch their motions; and, unaware of any danger to the shrimp from the grasp of the anemones, Charlie and I resolved to have some, and succeeded in capturing several. A very fine one instantly burrowed among the small stones and sand at the base of the aquarium, and seemed half dead. It took no notice of a small piece of meat held to it on the point of a quill, and appeared altogether dispirited. Meanwhile its companions betook themselves to the shadow of the sea-weeds, from which they shortly emerged, jerking about, if touched, with wonderful rapidity. But their prettiest motion was that of swimming. They did this very quickly, moving their feet and tail along like paddles. At first they were too shy to take the meat when of fered, though, if placed beside them, they would eat it; but they soon became tame, and seizing little bits of meat between their fore-legs, they eagerly devoured them. Our aquarium now went on pretty well for some weeks. We had at, different intervals placed in it a large number of anemones, some periwinkles, limpets, coat-of-mail animals, and one or two little fishes, and had derived much pleasure from watching them. But, after a time, we observed that our vase had not so healthy an appearance as we could desire. The sea-weeds looked paler, and the ends of the leaves became thinner and turned yellow. Orange-colored spots appeared on the red sea-weeds. Some anemones died, and all the fish perished. A piece of the stony coralline fell from one of the stones, and had an unpleasant odor. A limpet which had died, left on the stone where it had been fixed, a large spot, black as ink; and as we had never read or heard of such an occurence, and, though accustomed to observe the limpets on their native rock, had never seen these spots, it served to confirm the idea that something was wrong. Some periwinkles, which are always restless animals, but which had usually contented themselves with climbing to the topmost part of our artificial rocks, now quitted the aquarium altogether, and roamed over the carpet, leaving a white gauze-like streak in their track. One daring wanderer had even taken possession of a chair, and a visitor, who was just about seating herself, was suddenly checked by the exclamation of her little girl, "O mamma, mamma, you are sitting on a winkle." The water rapidly became turbid, and, when stirred, emitted an odor which warned us to empty the vase as quickly as possible. We were not easily discouraged, however; we had learned some lessons by our experience. We proceeded more systematically in future. We felt assured that our animals had been too numerous for the amount of sea-weeds, so we placed more of these, especially of the grassgreen kinds, in our aquarium. We became more careful in daily removing any floating fragments of sea-weeds, or any film or dust on the water. We protected our aquarium by a thin gauze veil over the top; and when we saw that the upper part of the water was less clear than the remainder, we drew this off with a siphon, and replaced it with clean water from the sea, and we kept the sides of the vessel free from any little green incrustation or salt, by cleasing them with a soft wet cloth. We soon found out, too, that as an evaporation is constantly going on, the water becomes less in quantity, and too salt for either animal or vegetable life. We were not fond of changing the water wholly, because we became aware that it contains a number of germs of sea-weeds or animals floating unseen, but springing up unexpectedly into life, so that our water was valuable. Mr. Gosse advises that about a teaspoonful of pure rainwater, in proportion to a pint of the sea-water, should be introduced every other day, and we gladly adopted this hint. From the work of this great naturalist we learned, too, the necessity of aërating the water, which, standing in an aquarium, is, even though aërated in some measure by the plants, yet naturally less fully so than that which glistens to the sunlight and the breeze, and is stirred by rolling waves. We found that a syringe, filled and emptied again and again, had a good effect; as had also the simple method of dipping a cup into the water, and pouring it out slowly, so as to cause air-bubbles at all parts of the vase, letting the water lie in full sunshine during the process. Again we commenced our search for animals. Charlie was anxious to get some sand-hoppers, (Talitrus,) those merry little things which jump up from the sands almost into one's face as we stoop down above them. In vain I suggested that these poor little creatures would stand no chance among the anemones, shrimps, prawns, and other animals. "We can but give them a trial," said Charlie; 66 we will take a few," and so we did. Far more lively in form and graceful in action than either shrimp or sand-hopper, was a fairy-like little prawn, which we secured as he was darting in and out of the sea-weeds fringing a pool, in company with several of his kindred. In our opinion the prawn outrivaled in attraction any of the inhabitants of our aquarium. The body was so clear that he looked as if cut out of delicate brown glass, and we could see his internal structure. He was marked with fine purplish lines, his joints seemed as if formed of amber, and his large black eyes were encircled by a rim of gold, and were on stalks. And O! what long slender thread-like horns he had! Three of these antennæ were placed on each side of his head, and some of them were much longer than his whole body. Every now and then they seemed to get entangled among our sea-weeds, so that one would fancy the animal must break or tear them off. 66 Never fear, Charlie," said I; " prawns are used to rocks with sharper angles than ours, and more thickly covered with tangling weeds, and no rough waves will be here to dash him into unexpected dangers; he will know how to take care of himself." Our little favorite was not full-grown. He had a remarkably strong beak between his eyes, and it was toothed like a saw, serving him as a means of tearing seaweeds, and also as a weapon of defense; though it was not till a later period, when we unfortunately admitted some very large prawns, that I became aware how well these animals can use these strong weapons. At first we saw little of our prawn's movements, as he proceeded to conceal himself among the sea-weeds, and when hunted from this retreat, hid fairly out of our way beneath one of our little archways. "I wish," said Charlie, "he would come out and swim about. Of what good will he be if he always lurks among seaweeds?" 66 Patience, Charlie; prawns as well as boys, have likings of their own wait a while;" and well did our prawn repay our waiting. As he emerged and glided past the green weeds, he seemed of delicate green too, as this tint shone through | his transparent body; and when he came in front of a clump of red weeds, he seemed of pale rose tint. We called him Crystal, and as he glided by a shrimp, the latter looked quite homely by the comparison; and I was confirmed in an opinion which I had before had, when watching groups of these creatures reveling in their native pool, and winding their long filaments amid its verdure, that nature scarcely offers a more graceful group of animated forms than is exhibited by the lively prawns. Crystal soon became so accustomed to take his food from the point of a quill, twice in every week, that the moment this appeared in the water, he would follow its |