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

396 COLLECTIONS FROM MELANESIA.Main skeleton strictly rectangular ;primary fibres '28 to -3;")millim. apart at surface, secondaries -24 to '28 millim. ;primaries•053 to '07 millim. in diameter, spicules 2- or 3-serial : secondaries•035 to •OT millim. in diameter, spicules uniserial ; horny matterstrong, pale amber-yellow, composing two thirds of the fibrein the primary, and five sixths in the secondary fibres. Dermalskeleton a strong, usually quadrangular network, tending to berectangular, of similar composition to the main skeleton ; betweenits meshes is intercalated a close angular network of finer andjmler uniserially spiculate fibre, •OlS to ^024 millim. in diameter, themeshes ^053 to -14: millim. in diameter. Sarcode pale umberbrown,granular. Spicule slightly bent, smooth acerate, taperinggradually to sharp points from three or four diameters from ends ;size -llo by •OOT millim.Hab. Alert and West Islands, Torres Straits, 7 fms. ; bottomsand.Three good and some more or less fragmentary specimens inspirit. The two largest are 120 and 115 millim. (4|- and 4|inches) in length. The largest is composed of two stems, a2)parentlyof independent origin, but one of them attached to and united withthe other at two points by broad masses of common substance. Thespecies is nearly allied to C. subarmic/era, and hardly differs at allexteriorly from the smooth form of that species except in its apparentlyslight tendency to form branches, but has the spicules ofabout twice the diameter, and much fewer in number in proportionto the horny matter, and the network of the main skeleton closer.It resembles Ohalina moataf/ui, Bowerbank (? Fleming) (GreatBritain), in the general form and the size and shape of tlie spicules ;but the fibre in that s])ecies is less horny and stout, and has but oneor two series of spicules.It is a curious fact that at one of the points of union between thetwo stems, as above described, a vent, originally belonging to one ofthe stems, seems to have come into communication with the canalsystemof the other stem.Cladochalina nuda, var. abruptispicula.(Plate XLI. fig. j.)Repent?, with single series of vents on one surface about 2 millim.in diameter, from 15 millim. and upwards apart, margins levelwith surface. Stem 8 to 12 millim. in diameter, slightly compressed,unbranched ; surface even. Colour, in dry state, brown. Texturetough, elastic. Main skeleton rectangular. Fibre strong, paleamber-yellow ; primary fibres about -088 millim. thick, spiculesaxial, about 3-serial, ^35 to -5 millim. apart, with a margin ofhorny matter ; secondary fibres, as primaries, but ^044 to "088 millim.thick, spicules somewhat loosely aggi'ogated, 1- to 3-serial. Dermalskeleton as in the typical form, but with stouter main fibres.Sarcode pale yellow-brown, transparent. Spicules smooth acerate,straight or almost so, coming abruptly to sharp i)oints within 1|diameter from ends ; size '107 bv -0063 millim.