This species of the _Sargassum_, found in such immense quantities, floating upon the surface of the ocean, is of a fine yellow colour, lighter or deeper in tint, being when very young of a greenish yellow colour; it is very buoyant, occasioned both by its lightness of structure and body of water to support it, as well as by the number of air vesicles with which it is profusely covered; it has a handsome appearance when seen spread out and swimming on the surface, or when just taken out of the water. On drying, it first retains the yellow, or greenish yellow, afterwards becoming of a reddish brown colour, but turning black, if exposed to the atmosphere when drying. The leaves are long, narrow, scattered, serrated at the edges in an irregular manner; the stems are studded with numerous air-vesicles in different stages of growth, spherical, and attached by a short pedicle to the stem. In many instances a young leaf would be seen emerging from the air-vesicle, and in others many of the leaves would have the air-vesicle (instead of being, as usual, on the stems) at the summit, forming a rounded termination to the leaf; some of the vesicles would have a longer and broader pedicle than usual, which assumed the character of an embryo leaf just forming, similar to what has been just mentioned as occurring.[97] All the weed was more or less profusely covered with parasitical _confervæ_, displaying much delicacy and beauty. I succeeded in capturing with the weed numerous specimens of small crabs, and some even of large size, small nereis, together with various specimens of fish, the _Syngnathus_, or pipe-fish, &c. The _Scyllea pelagica_ was also abundant, clinging to the plants; and also numerous small sepiæ of a beautiful purplish colour.