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

406 COLLECTIONS FKOM MELANESIA.nately from one side of the main stem at very acute angles, soonbecoming almost parallel with the stem itself ; their length variesfrom 60 to 120 millim. (2g to 4| inches). The vents are numerous,•5 to 1 millim. in diameter, circular, with sharp, prominent margins,about '5 to 1 millim. above the general surface ; ranged in a singlerow down each margin of the stem and branches, and also scattered(more sparsely) on their anterior and posterior faces ; they are 2 to5 millim. apart on the margins. General surface of sponge level,only rendered a little uneven by the slight elevations which carrythe vents, composed of a close mesliwork ; meshes •25 wide, *25 to•5 millim. apart. Texture firm, incompressible in stem, elastic,somewhat compressible towards ends of branches, brittle ; the surfaceand internal fibre soft, like leather. Colour in dry state— surfacepale grey ; interior brownish yellow in present specimens, owing to aparasitic microphyte of some kind. Sarcode apparently transparent,almost colourless.Main skeleton—meshes strictly rectangular, very close ;primaryfibres about '11 millim., secondaries about '14 millim. apart nearsurface ; horny material uniting fibres only visible distinctly at somedepth in the sponge ;primary fibres 3 or 4 spicules broad, secondaries2 or 8 spicules broad. Dermal skeleton composed of meshesof various sizes and a varying number of angles, formed by the projectingends of the primary main-skeleton fibres and the uppermostsecondary fibres. Horny matter almost colourless. Spicules— (1)skeleton acerate, smooth, slightly curved, tapering to sharp pointsfrom near middle ; size -16 by -0063 millim.Hah. Friday Island, Torres Straits.Distribution. " Probably Indian Ocean" {Lamarclc).Parasite. The horny matter of the fibres is covered with immensenumbers of a small, strongly refractive globular body about. -0015millim. in diameter, similar to that which gives a rust-brown colour^to the fibres of many Euspongice^ recently stated by Prof. F. E.Schulze (•' Der Badeschwamm," Westermann's Illustr. Deutsch.Monatshefte, 1882, pp. 188-210) to be probably of parasitic nature.Certainly, judging by the friable character of these and other similarlyaffected specimens, these bodies would appear to have exercisedsome distinctly deteriorating influence.EENIERID.^.Reiiierida, Carter, Ann. ^ Mag. N. H. (4) xvi. p. 133.Under this heading I include only those Monactinellida which havemerely acerate spicules not enclosed in a distinct horny fibre. Thegenus Reniera very commonly has strong indications of a hornymaterial uniting the ends of the spicules, and thus approachesChalina and PacJij/cJudina, where, however, the horny element isdistinct enough to bear the name of a fibre ; but there is no sharp linebetween the llenierida3 and Chalinidae. In several cases, where thespecimens have been imperfect, T have preferred to give no specific