PENNATTLA, a genus of zoophytes (anthozoa), allied to gorgou ia (q.v.) and a/evonium (q.v.). and having very similar polyps; but the polyp mass is not fixed by is base, has a fleshy stem strengthened by a bone, and a skin containing calcareous spiculx, the upper part of the stem winged on two sides, with numerous pinine, along the upper margins of which the polyp-cells are ranged. The whole form somewhat resembles a quill. so that the popular name SEA PEN is very often given to these zoophytes. One spe cies pennatubs phosphorea, is common on the northern parts of the British coast. It is from two to in length, of a purplish-red color, and like many—perhaps all— of the other species, is sometimes brilliantly phosphorescent, emitting flashes of light when disturbed, but ceasing to be luminous on relapsing into quiescence. The stalk is hollow in the center, and thebone which it contains—and which is composed of phos phate and carbonate of lime, like the bones of the vertebrate animals—is a very remarks hle part of its structure, not extending the whole length of the stalk, slender, straight. and perfectly simple, but bent backwards at each end into a hook. Other species are
found in the Mediterranean and other seas, some of them more pen-like than even the British one. It has been alleged that they swim by contractions and dilatations of their common fleshy substance, or by movements of the pinnee; but there is no good evidence of their possessing any such power of locomotion, which is very contrary to the analogy of all similar zoophytes, and more probably the opinion prevalent among the fishermen of the Scottish coasts is the correct one, that their natural place is at the bottom. of the sea, with the somewhat flexible lower end of the stalk immersed in mud. Nearly allied to the pennatulfe is another genus of extremely beautiful zoophytes, virgularia, ranked with them in the family pennettulichr, and sometimes receiving the popular name SEA Hum. One species, V. /nimbi/is, is found on the British coasts. It resembles a slender rod, bearing throughout the greater part of its length two rows of lobes, along the mar gin of which the polyps are arranged. The whole length is from six to ten inches.