Report on the zoological collections made in the Indo-Pacific Ocean ...

458 COLLECTION'S FROM MELANESIA,the present form provisionally to that species, with which it agreesmuch better than the form which I named E. nervosum (Journ. Linn.Soc, Zool. XV. p. 496). As to the locality at which S. cancellatawas obtained, we have no more particular knowledge than that itwas obtained bj' MM. Peron and Lesueur. As these travellers seemto have collected, among other places, on the north coast of Australia,this fact supports, if any thing, the above view as to its identity withthe present species. In any case it will be best to describe the latterfully :—Erect, flabellato, clathrous. A short main stem gives riseto a clathrous reticulation lying in one plane, in which the originalbranches are only distinguishable near the base, lleticulation close,regular ; meshes oval, the longest diameter lying in direction oflong axis of sponge, about 10 by 5 millim. in average dimensions ;the meshes form deep cells, occasionally closed by a septum ofsponge-substance. The stem, branches, and the bars which completethe reticulation are oblong in transverse section, with roundedmargins ; hence the lateral surfaces are flat and the antero-posteriorones are rounded. Antero-posterior diameter of stem 32 millim.,lateral diameter 18 millim. ; antero-posterior diameter of the barswhich form the ultimate reticulation about 10 millim., lateral diameterabout G millim. A slight tendency to proliferation so as toform expansions parallel to the main plane of the sponge is shownby formation of a few meshes on the surfaces of the frond. Terminationsof branches either united by connecting bars or projectingslightly as rounded lobose ends. Surface in dry (macerated) statequite even, appearing minutely reticulate. Texture firm, that ofstem woody ; substance of branches and reticulation rather brittle,slightly compressible ; colour, in macerated condition, very paleyellow-brown.Main skeleton rectangular in arrangement; primary fibres only projectingfrom surface by the tuft of echinating spicules which terminatesthem, compact, about 8 to 10 spicules broad; distance betweenthem at surface about -4 millim. ; echinated sparsely in interior,abundantly near surface of sponge, with the echinating spicule :secondary fibres compact, about 3 to 6 spicules broad, about•3 millim, apart, echinated abundantly with the echinating spicule.Dermal skeleton consisting of an irregular network with rectangularmeshes, the meshes generally not exceeding -55 millim. in diameter;fibre compact, about 10 spicules broad, well echinated with theechinating spicule. Horny uniting material occasionally distinguishableoutside fibre as a pale yellow transparent substance.Sarcode? (absent). Spicules:—(1) Skeleton acerate, smooth, slightlycurved, tapering to sharp points from within about four diameters ofthe ends ; size '22 by '0127 millim. (2) Echinating cylindrical,epined ; both ends well rounded ; spicule tapering slightly frombase to apex ; the apex about half the diameter of the base ; spinesdistributed all over the spicule, rather more abundantly at baseand near apex than elsewhere ; those of the proximal half or onethird of the spicule rather small, straight, sharp, the remainderlonger, curved towards base ; size of spicule -15 by "01 millim. : scat-