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Show 1867.J DR. J. E. GRAY ON SPONGES. 517 Var. Spongia scypha, Mont. W. Th. ii. p. 107, t. 15. f. 1. S. foliaceus, Gray. See also- Phakellia robusta, Bowerb. B. S. ii. p. 126, f. 367 (fan-shaped). Subsection 2. Spicular Sponges (SPICULOSPONGLE). Sponge fleshy, more or less strengthened by fasciculated or scattered siliceous spicules, the fascicules being sometimes slightly covered with a thin layer of horny matter. Sarcode generally abundant, granular , or fleshy ; sometimes it is mucilaginous and early deciduous, as in Euplectella. Oxyospongiee, Duchass. & Michelotti, Spon. Mer Caraibe. The three principal families of this group are distinguished by the absence or the presence of certain kinds of spicules ; thus the Esperiadee have bihamate "defensive " spicules, whilst the Tethyadee have three-pronged or three-hooked and stellate spicules, and all the kinds are absent in the Halichondriada;. The Euplectelladee and Polymastidee are distinguished by the textile structure of their tubular body ; the former has several kinds of defensive spicula, which are absent in the latter family. Order III. LEIOSPONGIA, or Unarmed Sponges. Sponge with all the spicules of the same kind, often varying more or less in size and form, but they are always modifications of the most simple kind of spicules. The spicules are not all uniform in shape; but, if varying in shape, they all belong to one type of form. Thus they may be either cylindrical, fusiform, needle-shaped or pin-shaped, or any of the intermediate modifications of these shapes, which sometimes insensibly pass into each other. In some of these sponges all the spicules are of one or the other of these modifications; others contain two, and others again all three, of these forms combined together. They are easily known from the sponges of the next order by the entire absence (except in some very rare instances) of any of the spicules that Dr. Bowerbank has called defensive and retentive spicules-that is to say, bihamate, anchorate, birotulate, stellate, or three-pronged spicules. The fusiform, needle-like, pin-shaped, and cylindrical spicules belong to a series, and these forms gradually pass into each other ; that is to say, there are all intermediate forms ; sometimes the spicules of one sponge, or even specimen, present more than one form. These spicules are smooth, or partially or entirely spiculated or tuberculated, or they are furnished with smooth or rugose or spinous rings. They are rarely angularly bent in the middle, or curved at each end and bent in the form of an S. I have never seen the two ends bent up on one side, such double-hooked spines belong to the bihamate series, and are generally undeveloped spicules of that form. With |