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Show 1867.] DR. J. E. GRAY ON SRONGES. 505 SYNOPSIS OF GENERA AND SPECIES. Section I. MALACOSFORJ-E, or Sponges with soft spores or gemmules. Reproduction by ova contained in a thin membranaceous ovisac not strengthened by spicules or by gemmules, scattered in the substance of the sponge. These sponges are easily known by the absence of the hard siliceous or siliceous-armed ovisacs that are to he found adundantly in the substance of those of the following section. Subsection 1. Netted Sponges (DICTYOSPONGI^E). Skeleton formed of a continuous siliceous or horny network. The fleshy part of the sponge is generally gelatinous and dried up, leaving little to be observed in the dry sponges, and often easily washed away. Order I. CORALLIOSPONGIA. Sponge hard, coral-like. Skeleton entirely formed of siliceous spicules, anchylosed together by siliceous matter, forming a netted mass covered with sarcode. The skeleton is formed of large siliceous spicules anchylosed together by siliceous matter. The sponges in which the siliceous element is the most developed are siliceous sponges par excellence. Fam. 1. DACTYLOCALYCID^E. Sponge massive, expanded or flabellate; the network with angular meshes. Lithospongice, Duchass. & Michel. Spong. Caraib. p. 25. This beautiful family of sponges is at once known by having the skeleton formed of continuous anastomosing fibres formed of concentric lamina of silica, forming a hard brittle network. W h e n alive they are covered with a continuous external skin, which is pierced with oscules on the upper and sometimes on the lower surface. As most of the species have been described at length in the ' Proceedings of the Society/ I only give a synopsis of the genera for the purpose of bringing them together in one view. * Network irregular, not symmetrical. 1. DACTYLOCALYX. Dactylocalyx, Stutchbury, P. Z. S. 1841, p. 86; Bowerbank, B. Sponges, i. p. 203 ; ii. p. 11 (Dactylochalix, Bowerbank, in B. M.) Lphyteon, Valenc. Institut. Sponge expanded, with large sunken grooves and oscules on the upper and lower surface. Spicules of skeleton tuberculated; spicular network rugose, tubercular. Sarcode with scattered radiated or stellate spicules, divided into branches near the base, and with knobs at the tip of the rays. Sarcode studded with many-rayed stellate spicules ; the six prin- |