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

470 COLLECTIONS FROM MELANESIA.Internal skeleton formed by a coarse network of loose spiculo-fibre,the subcortical ends of the fibres rising up so as to support thecortex. A strong cortex composed of a zone of chiefly subhorizontalskeleton-spicules united by sarcodic substance, and about -45 millim.in thickness.Spicules :—(1) Skeleton spinulate, very large, decidedly curved,tapering gradually to a sharp point ; head oval, shaft taperingslightly towards it, forming a decided but slight neck ; size '8by "035 millim. (2) Spinispirular, either delicate, long, composedof about three bends, which are gradual, so that no part of the wholespicule lies much out of the straight line ; size '05 to -OoG by -0016millim. ; or, rather stouter and shorter, with only two bends, size•032 by "0022 millim.; in either case about 10 spines to a bend;spines slender, sharp-pointed, '0022 to -0032 millim. long.Hah. Thursday Island, Torres Straits, 4-5 fms.The, unfortunately, single and dry specimen measures 35 millim.(1;? inch) high by 25 millim. (1 inch) in extreme breadth.The species has in the dry state the colour and much of theappearance of >S'. var/abiinda ; both forms of spicule, however, areconsiderably larger than in that form and the angulation of theflesh-spicule is less abrupt. It is, however, undoubtedly nearlyrelated to it.100, Spirastrella decumbens. (Plate XLIII. fig. c.)Incrusting, thin ('5 to 10 millim. thick). General surface level(except where affected by the inequalities of the substance to whichit is attached), glabrous. Colour in sjnrit grey, slightly tingedwith pink. Vents not made out with certainty. Texture toughand leathery. Internal structure very compact ; no large spacesseen, as a rule, in vertical sections. Sarcode dull greenish, subtransparent,coloured diffusely. Skeleton consisting of loose spiculartracts, about 6 to 10 spicules broad, running obliquely or at rightangles to the surface, and occasionally forming slight prominences,protected by the cortex, and of loose skeleton-spicules lying in alldirections between them. Cortex consisting of a layer, two or threespicules deep, of the flesh-spicule, lying in almost colourless sarcode.Spicules :—(1) Skeleton spinulate, slender, tapering very graduallyto a sharp point, and very gradually also to the head, below whichthe shaft forms a decided and well-defined neck ; head oval, ratherpointed at free end, of about the same diameter as the middle of theshaft, viz. '0095 millim. ; length of sincule "35 millim. (2) Spinispirular,moderately stout to stout, consisting of two bends, about12 spines to a bend ; spines strong, tapering from broad bases tosharp points, length about '0045 millim. ; length of spicule "025millim., thickness (excluding spines) '0032 to '0063 millim.Hab. Alert Island, Torres Straits, 7 fms. (growing over a tubularRetejjora).This species appears to be more nearly allied in its spiculation toS. {Alcyonium) purpurea, Lamarck, than to any other Indo-Pacificspecies, but it differs from it in wanting the magnificent crimson colour