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

;SPONGIIDA. 405has a slightly but regularly uneven surface, the tissue covering itbeing, however, almost smooth. Vents with thin everted marginsabout -5 millim. high, abundant, irregularly uniserial, 1 to 3 millim.in diameter on one (presumably the upper) side of the stem andbranches, less abundant and generally smaller on the opposite side.Branching dichotomous, at angles of 50° to 60° ; the branches ratherflexuous ; branches and stem 8 to 18 millim. in diameter. Texturein spirit firm, but flexible, tough ; colour dark dull grey. Mainskeleton composed of tough, flexible primary fibres of closely packedspicules, about 6- to i2-serial, running approximately at rightangles to surface (no horny uuiting-matter visible), the fibresnearly approximated to each other ; and of irregular and often loosecrossing secondary tracts of spicules 2 to -i spicules broad, not strictlyat right angles to primaries. Dermal skeleton a closely-set coat ofsubparallel spiculo-fibres about 8 spicules broad. Barcode darkbrownish, granular. Spicules accrate, slightly but sharply bent,tapering slightly from middle, and rather suddenly from withinabout two diameters of ends, to moderately sharp points ; size -2 by•0128 milhm.Hah. Port Darwin, 7-12 fms. ; bottom mud and sand.Distribution. East-Indian seas {Esper)'!The only specimen measures 150 millim. (6 inches) in extremelength. The species is at any rate distinct from Spongia arhoresceyisof Lamarck, who gives S. lobata, Esper, as a sj'nouym of his species.It stands on the borderland between Pacinichalina and the branchedand large-vented Renieridoe. I assign it to the former, as its fibresare evidently formed in part by a flexible horny material. It differsfrom the described specimens of S.'lohata in having approximatelycylindrical branches and bearrng some vents on both sides.36. Pachyclialina macrodactyla. (Plate XL. figs. B, B';Plate XLI. fig. o.)Spongia macrodactyla, Lamarck^ Ann. Mus. Hist. Nat. xx. p. 457.Guided only by the short and superficial description given byLamarck, and by the locality (" probably Indian Ocean ") assignedby him, I refer to his species some dry fragments of an exquisitePachychalina, possibly originally belonging to one specimen. ItLas some external resemblance to Spongia asparagus, Lamarck, ofwhich I have seen a specimen ; but the branches in the latter arecylindrical, the vents open on the level of the general surface,and the fibre-structure is that of Chalina rather than PachgcJudina.I will proceed to supplement the original incomplete descrijjtion bya fuller one.The stem and branches are flattened out, somewhat knife-like, inmost places, the edges being sometimes quite sharp ; the lateraldiameter is here about twice the antero-posterior one (viz. about 13millim. at largest part of stem, millim. just below apex of branches)the stem near the base appears to be normally cylindrical, about 6millim. in diameter. Branches (in present specimens) given off" pin-