We shall not attempt to describe the different species of zoophytes and annelides, amounting to hundreds--indeed, they are not all familiar to scientific men. We have little more to say of the crustacea that go scrambling about, yet it would be impossible to overlook that peripatetic whelk-shell, which climbs about the stones with such marvellous activity. On a narrower inspection we perceive that it moves by a foreign agency. Those sprawling legs protruding from its mouth discover the hermit crab, which is obliged to dress its soft body in the first defensible armour it can pick up. A deserted whelk or common spiral shell is its favourite resort, but, like many bipeds, it has a love of changing its house; and those who have narrowly watched its habits state that it will deliberately turn over the empty shells upon the beach, and, after examining them carefully with its claws, pop its body out of one habitation into another, in order to obtain the best possible fit. But there are still stranger facts connected with this intelligent little crustacean. We have before observed that the parasitic sea-anemone invariably fixes itself when possible upon this movable house, perfectly regardless of the many bumps and rubs which necessarily fall to its lot. Another warm friend, the cloak-anemone, clings still closer, for it perfectly envelopes the lip of the shell with its living mantle. Our hermit has still a third intimate acquaintance, who sponges upon him for bed and board, in the shape of a beautiful worm, _Nereis bilineata_, which stows itself behind the crab in the attic of the whelk-shell, and, the moment its protector by his motions indicates that he has procured food, glides between the two left-foot jaws, and drags a portion of the morsel from his mouth, the crab appearing to evince no more animosity at the seizure than the Quaker who suddenly finds his spoons taken for church-rates. The interesting specimens we have dwelt upon are confined to the sea-water tanks, which line the Aquarium on the side opposite the door, and those which run down the centre of the apartment. _Vis-à-vis_ are the fresh-water tanks, in which we may watch the habits of British fishes. There is a noble pike lying as still as a stone--a model sitter for the photographer who lately took his portrait. The barbel, bream, dace, and gudgeon are seen going about their daily duties as though they were at the bottom of the Thames, instead of sandwiched between two panes of glass, and inspected on either side by curious eyes. Those who go early in the morning will have a chance of seeing the lampreys hanging like leeches from the glass by their circular mouths, and breathing by the seven holes which run beside their pectoral fins. The marine fish should also be studied; strange forms with vicious-looking jaws, the dog-fish for example, which is a young fry as yet, but which will grow a yard or two in length.