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Show 122 DR. J. E. GRAY ON HYALONEMA LUSITANICUM. [Jail. 24, I consider that this structure of the corium is enough to prove that it is the community of polypes that constitute the bark that forms the coil of spicules, and that they are too intimately connected with the spicules to be only parasitic on their surface. IV. The essential character of a sponge is, that it is permeated by canals for the circulation of the water which is emitted by oscules ; and there is no such structure in Hyalonema. The sponge in which the Japanese Hyalonema is found is of the normal structure here noted. But there is no appearance of any canal in the coil of spicules; indeed they are all formed into a close mass, adherent together by the corium that surrounds each spicule. There is no communication between the canals of the sponge to which the Hyalonema is attached and the axis of Hyalonema, which has been regarded as part of the sponge. The sponge forms a condensed hard case, round the base of the coil which is inserted in the sponge, very different from the rest of the sponge, of a dense structure, and without any canal in it, as if to separate the base of the Hyalonema from it as completely as possible, evidently regarding the Hyalonema as an intruder, I suppose, the base being enclosed in the hard case without any canal, and the upper free part of the axis being entirely covered with the polype-bearing corium or bark (or with the mass of parasitic Palythoee, if that theory be the correct one) ; and I have seen specimens which show that in the perfect state of the animal the axis is so covered. This bark being destitute of pores or other apertures, and the axis destitute of any canal, shows that the axis and bark cannot be any part of the "cloacal system," as Dr. Bowerbank states them to be in his characters of the genus, and, indeed, have no connexion with the sponge in which jt lives. In the perfectly formed specimen the coil of the axis reaches to the base of the sponge, the coil gradually tapering in thickness until it reaches the base, where it is like a small pencil of very thin spicules. This thin end or pencil is closed over by the sponge. I believe that the coral commences on the surface of the sponge ; and that as the coral increases in size the basal portion perforates and descends in the sponge as the upper part of the axis ascends or enlarges in size. In fact the coil of spicules forms no part of the organization, and has no organic connexion with the sponge in which it is placed, there being no water-current between it and the sponge, which is the essential character of sponges. It is to be observed that neither M . Valenciennes, Professor Max Schultze, nor Dr. Bowerbank attempt to prove that the coil is in any way organically connected with the sponge. V. The attachment to the sponge appears to be the habit of a single species ; for the Portuguese species, which agrees with the Japanese in most of its essential characters, lives free in the sea and has |