The braided-hair weed, Plocamium, from plokamos, braided hair, is the pinky-red, ribless, much-branched, rather gristly weed, which, from its elegant arborescence and beautiful color, is an especial favorite with the workers in ornamental sea-weed decorations. It is cast up in quantities on the British shores; but, as a rule, it lives beyond the shore, that is to say, below low-tide level. Another equally common weed has a slightly darker red color, and its frond is horny, flat, branching in twos, and with little fronds on the edges. It is found from the very verge of high water to the extreme of low water, fringing the margins of the rock-pools, and is very common. From its hard condition and horny nature it has been called Gelidium, from _gelu_, frost. The beautiful red weed, whose resemblance to a great branching tree pressed flat is so great, and which bears thousands of little berry-looking knobs on short stalks, on the sides of its fronds, is called Sphærococcus, or globe-fruit or berry. It is not known on the eastern coast of Britain, but is common on the Irish shores at extreme low-water mark. Another red weed, with a dull purple color, has a frond of from six inches to two feet in length, and every minute ramification of its skeleton-leaved frond has one or more berry-shaped swellings. It is common all round the coast within tide-marks, and has been called after a genus of mosses, Hypnæa. The last kinds of filamentous, or skeleton-leaved red weeds, to be noticed, are remarkable for their tufty nature, their spreading out in water and showing tree-like branching from a stem, which, when magnified, is seen to be made up of many long cells placed side by side. Some live between tides on rocks, and others at the edge of low tide, but the most interesting are parasitic upon other weeds. From their many-tubed nature they are called Polysiphonia. The parasitic kind (so named) is rather rare, and settles on some of the calcareous weeds. The lanceolate kind is found on the stems and fronds of the tangle; and a dark red species, called Formosa, is found near low-water mark. Brodie’s Polysiphonia is known by the little tufts of branches which come from the main branches, and it has a good stem. It is found on corallines and on rocks. The fibrous Polysiphonia has tufts at the end of its branches, and is found on mussel-shells; and the violet kind is brownish-red or purple, has a small root-like disk, and fronds which are from six to ten inches in length. It is feathery and much branched.