Sea-Weeds, Shells and Fossils

SEA-WEEDS, SHELLS and FOSSILS.
PETER GRAY, A.B.S. Edin.; AND B. B. WOODWARD,
Of the British Museum (Natural History), South Kensington.

Butler & Tanner, The Selwood Printing Works Frome, and London.

SEA-WEEDS.
By PETER GRAY.
Algæ, popularly known as sea-weeds, although many species are inhabitants of fresh water, or grow on moist ground, may be briefly described as cellular, flowerless plants, having no proper roots, but imbibing nutriment by their whole surface from the medium in which they grow. As far as has been ascertained, the total number of species is about 9000 or 10,000. Many of them are microscopic, as the Desmids and Diatoms, others, as Lessonia, and some of the larger Laminariæ (oarweeds), are arborescent, covering the bed of the sea around the coast with a submarine forest; while in the Pacific, off the northwestern shores of America, Nereocystis, a genus allied to Laminaria, has a stem over 300 feet in length, which, although not thicker than whipcord, is stout enough to moor a bladder, barrel-shaped, six or seven feet long, and crowned with a tuft of fifty leaves or more, each from thirty to forty feet in length. This vegetable buoy is a favourite resting place of the sea otter; and where the plant exists in any quantity, the surface of the sea is rendered impassable to boats. The stem of Macrocystis, which girds the globe in the southern temperate zone, is stated to extend sometimes to the enormous length of 1500 feet. It is no thicker than the finger anywhere, and the upper branches are as slender as pack-thread; but at the base of each leaf there is placed a buoy, in the shape of a vesicle filled with air.