as thin as silver-paper, all puckered and folded at the edge, and generally torn and fretted into holes. (See Plate III). It is abundant in the hollows of the rocks between tide-marks, extending and thriving even almost to the level of high water, and bearing with impunity the burning rays of the summer's sun, provided it be actually covered with a stratum of water, even though this be quite tepid. It therefore is more tolerant than usual of the limited space and profuse light of an Aquarium, where it will grow prosperously for years, giving out abundantly its bubbles of oxygen gas all day long. It is readily found, but owing to the excessive slenderness of its attachment to the rock, and its great fragility, it is not one of the easiest to be obtained in an available state. The Enteromorphæ have the same qualities and habits, but their length and narrowness make them less elegant. The Cladophoræ, however, are desirable; they are plants of very simple structure, consisting of jointed threads, which grow in dense brushes or tufts of various tints of green. Some of them are very brilliant; the commonest kind is C. rupestris, which is of a dark bluish-green; it is abundant on all the ledges in this neighbourhood. (See Plate III)
These are a few of the sorts of sea-plants which are met with in the situations I have described. In order to transfer them to an Aquarium, a portion of the rock on which they are growing must be removed. These plants have no proper roots, and therefore cannot be dug up and replanted like an orchis or a violet, but adhere by a minute disk to the surface of the rock,
