Virgularia mirabilis is undoubtedly one of the finest polypidoms found in the ocean. Two series of half-moon shaped wings, obliquely horizontal, are placed symmetrically round an upright axis. They embrace the stem somewhat in the manner termed petiolate by botanists, clasping it alternately; or, shall we say, like two broad ribbons rolled round a stem in an inverse direction, in such a manner as to produce the effect of two opposing flights of stairs. These wings are waving, vandyked, and fringed on their outer edge, and of a brilliant yellow; the dentature of the fringe being the lodging of their pretty little polyps, which display occasionally their gaping mouths and expanded gills. The polyps are white and semi-transparent. When they display their rays, the margin of each wing presents an edging of silvery stars.
Fig. 63. Branch of Virgularia, enlarged.
The Umbellularia have a very long stem, supported by a bone (Fig. 64) of the same length, and terminated at the summit only by a cluster of polyps. They have been found in the Greenland and other northern seas.
The Veretillum, which inhabit the Mediterranean (Fig. 65), have a simple cylindrical body, without branchiæ, and a rudimentary polypidom, furnished with very large polyps of a whitish colour.
IV. THE ALCYONARIA PROPER.
Fig. 64. Umbellularia
Greculandrea
(Lamarck).
The beings which compose this group have the fleshy polypidom always adherent, without axis or solid interior stem. They are divided into four families or tribes. One of these, the Cornularia, are zoophytes, and live in isolation, or gathered together in small numbers on the surface of a common membraniform expansion. The Cornularia cornucopia live on the coast of Naples, C. crassa on the Algerian coast. Other genera make their appearance on the coast of Scotland, of Norway, in the Red Sea, and in the Indian Ocean they appear in great numbers.
In the Alcyonaria, properly so called, the polypidom is very thick, of a semi-cartilaginous consistence, granular, and rough to the touch.