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Show 1881.] THE SURVEY OE H.M.S. 'ALERT.' 115 out, however, in almost every piece examined, and aie well preserved and constant in their positions. Hab. Sandy Point, 7-10 fathoms (on a piece of shell). This specimen is finely preserved and is probably young. Obs. The formation of the axial network mainly by short acuate spicules, and echination of the axial column by isolated long acuates in addition to the diverging columns, distinguish, at any rate by the perfection to which they are here carried out, this species from all the species which have been assigned to either of the closely allied genera Phakellia and Dictyocylindrus. . The absence of cylindrical spicules differentiates it from P.ventilabrum&ndP.folium, Sdt., but can hardly be said to ally it very closely to the other two species, P. robusta and P. tenax, which are similarly circumstanced; for in the one the long isolated acuates are wanting, and in the other a small spined cylindrical echinates the fibres. The long acuate occurs, however, in many other Axinellida. Probably Axinella cinnamomea, Sdt., from the Adriatic and Algiers, is the species most closely allied to ours, of known forms-though the short acuate is scarcely bent at all as it is here, and it wants the very stout long and short acuates which seem to connect this species with the Atlantic species A. mas-tophora, where these assume such a striking size. Some of the chief differences between P. cinnamomea, Sdt., and this Sponge m a y be thus stated :- Acerate Spicules. /'Sharply bent, tapering Axinella cinnamomea, Sdt. (Adriatic audi Algiers). gradually. Size "444 by "01267 millim. Phakellia cyreqia (As in preceding. Size (Straits of Magel--{ -304 by01267 m m . Ian). 1^ Shorter Slender Acuate. Very scarce; possibly not proper to sponge; slightly bent. Size •2837 to '3863 by •01086 to -01267 millim. Very abundant; sharply bent. Size '2534 by -0095 millim. Stout Acuate. Wanting. Two sizes occui\ Order H O L O R R H A P H I D O T A , Carter. CIOCALYPTA CALVA, sp. n. (Plate X. fig. 7.) Massive. Surface smooth. Structure of Sponge cavernous. Colour whitish. Skeleton of widely separate spiculo-fibres rising from base, where they are contorted and form a layer. Fibres stout, flattened, multispicular, spicules parallel in them ; at base containing a margin of sarcode of one fourth of diameter of fibre, superiorly becoming approximately Holorrhaphidote ; beginning to branch and anastomose about halfway between base and dermis, ending in dermal membrane in tufts of slightly diverging spicules, which spread on the membrane without meeting neighbouring tufts. Dermis otherwise naked, subopaque, thin, fragile. Skeleton-spi-cule acuate, slightly bent, tapering from head to a sharp point, size '577 bv '01267 millim. No flesh-spicule. J 8* |
