To procure specimens for the aquarium requires some knack and knowledge.  The sea-shore must be haunted, and even the deep sea explored.  At the extreme low-water of new or full moon tides, the rocks and tide-pools are to be zealously hunted over by the aquarian naturalist.  Several wide-mouthed vials and stone jars are necessary; and we would repeat, that no plant should be taken, unless its attachment is preserved.  It is often a long and difficult job to get some of the Algae; with their tender connections unsevered from the hard rock, which must be chipped away with the chisel, and often with the blows of the hammer deadened by being struck under water.  It is by lifting up the overhanging masses of slimy fuel, tangles, and sea-grass, that we find the delicate varieties, as the Chondrus with its metallic lustre, and the red Algae, or the stony Corallina, which delights in the obscurity of shaded pools.

The sea-weeds will be found studded with mollusks,—­as Snails and Periwinkles of many queer varieties.  Anemones, of the more common kinds, are found clinging to smooth stones.  Crabs on the sand.  Prawns, Shrimps, Medusae, and fishes of many species, in the little pools which the tide leaves behind, and which it will require a sharp eye and a quick hand to explore with success.  But the rarer forms of Actinias, Star-fishes, Sepioles, Madrepores, Annelidae, and Zoophytes, of a thousand shapes, live on the bottom, in deep water, and must be captured there.

For this purpose we must dredge from a boat, under sail.  The naturalist’s dredge is an improved oyster-dredge, with each of the two long sides of the mouth made into a scraping lip of iron.  The body is made of spun-yarn, or fishing-line, netted into a small mesh.  Two long triangles are attached by a hinge to the two short sides of the frame, and meeting in front, at some distance from the mouth, are connected by a swivel-joint.  To this the dragging rope is bent, which must be three times as long, in dredging, as the depth of the water.  This is fastened to the stern of a boat under sail, and thus the bottom is raked of all sorts of objects; among which, on emptying the net, many living creatures for the aquarium are found.  These may be placed temporarily in jars; though plants, mollusks, Crustacea and Actiniae may be kept and transmitted long distances packed in layers of moist sea-weed.

For all this detail, labor, and patient care, we may reasonably find two great objects:  first, the cultivation and advancement of natural science; second, the purest delight and healthiest amusement.

In the aquarium we have a most convenient field for the study of Natural History:  to learn the varieties, nature, names, habits, and peculiarities of those endless forms of animated existence which dwell in the hidden depths of the sea, and at the same time to improve our minds by cultivating our powers of observation.

The pleasure derived from the aquarium comes from the excitement of finding and collecting specimens, as well as from watching the tank itself.  There can be no more pleasant accompaniment to the sea-side walk of the casual visitor or summer resident of a watering-place, than to search for marine plants and animals among the fissures, rocks, and tide-pools of the sea-washed beach or cape.