Page:Hardwicke's Science-Gossip - Volume 1.pdf/195

grey creature of the element, it spreads rapid destruction around the place of its vegetation. It is only from one to two inches in height, and is exceedingly slender and delicate (figs. 7, 8). The vesicles

have been compared to a lily or pomegranate flower just opened; but they seem to vary with age. It sometimes grows on sea-weed and old shells, but is far less graceful than when growing on kindred zoophyes.

The Seak-oak Coralline (Sertularia pumila) is of a greenish colour, and occurs in considerable abundance as a parasite on some kinds of sea-wrack (figs. 9, 10), the common Fucus serratus being invested by such quantities of it as almost to weigh down the fronds near ebb tide. The shoots are seldom more than half an inch in height, thread-like, and sparingly branched. The animals have fourteen or sixteen tentacles, and when these are displayed, the hydra usually extrudes its body far beyond the rim of the cell. There is also the Snail Trefoil Coralline (Sertularia rugosa), which is found as a parasite on the fronds of the "sea-mat," as well as sea-weeds. Also the Sea-hair Corlline (Sertularia operculata), which is common on all parts of the coast, growing attached to sea-weeds (figs. 11, 12). It reaches from three to six inches in height, and, after a storm, lumps as large as a child's fist are washed ashore.

The slender branches grow in tufts, like bunches of hair.

"It was from the great resemblance," says Dr. Johnston, "of the vesicles to the capsules of mosses that the early botanists drew an additional argument in behalf of the vegetability of the corallines themselves." And a Darwinian might be, perhaps, forgiven, were he even now to feign how the Nereids

stole them from the mossy habitats of Flora's winter and vernal shows, to deck and gem the arbuscular garnitures of their coral caves.

The Sea-mat (Flustra foliacea) is by the Scottish fishermen in their meagre vocabulary denominated