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

434 COLLECTIONS FROM MELANESIA.primary skeleton- fibres ; the canals I have mentioned range in diameterfrom about •07 to -14 millim. This opening of a considerableproportion of the ciliated chambers directly into moderately widecanals agrees with what Vosmaer finds to be the arrangement inmany forms of the other Mouactinellid families Ileuierida3 and Suberitidte,as well as in a few other forms, viz. his third type (' Anteekeningenover Leucandra aspcra, H.,' Leyden, 1880, and TijdscbriftNederl. Dierk. Vereen. v. p. 144 et seq.).67. lotrochota purpurea.(Plate XXXIX. fig. L ; Plate XLII. figs, e-e"".)Halichondria purpurea, Boiverbank, P. Z. S. 1875, p. 293.Dr. Bowerbank's specimen (from the Straits of Malacca) is evidentlyquite young ; the present fine series of specimens, both dryand in spirit (numbering upwards of twenty), gives a better idea ofthe charactei's of the species.The external form is usually that of a cylindrical column, narrow,diminishing gradually in thickness towards apex, viz. from about 15millim. at base to 4 millim. at apex in adult specimens, dividingtowards the apex into two or three subequal branches ; it is sometimesflattened irregularly near the base ; it occasionally forms abroad palmate frond or irregular erect expansion, or an irregularlyhoneycombed horizontal mass which may attain a diameter of 65millim. (2| inches). The surface is broken up into a forest ofpointed or ridge-like monticular elevations, 1-3 millim. apart, 1-3millim. high. In the typical specimen (dry) the surface aculeationsare only -5 to 1 millim. apart and the same in height. Texture inspirit rather firm, but soft on surface, tough and flexible ; in drystate harsh on surface, rather brittle : colour in spirit very deeppurple, in drj- state dark green or pale purple. 8kcleton rectangular,consisting of stout compact primary spiculo-fibres devoid of visiblehorny material, 10 to iiO spicules broad, and of similar secondaryfibres 1 to 3 spicules broad. Skeleton -spicules smooth, acuate,rather squarely rounded at base, tapering to a sharp point from aboutfive diameters from end; size chiefly -26 by -0063 millim., a fewin the interior of the primary fibres '18 by -005 to -OOi'o millim. (inthe type the prevailing size is '16 by •0127 millim. and the spiculefrequently increases in diameter from the base towards the centre).Flesh-spicule birotulate (not eqnianchorate, as stated by Bowerbank),shatt verj' slender ; rotulse small, umbrella-shaped, with four equalcurved teeth ; length of spicule "016 to ^019 millim. Sarcode inspirit dark purple, granular ;in dry state either dark purple or darkgreenish. Large specimens attain a height of about 150 millim.(6 inches).Hab. Torres Straits, various localities down to 10 fms, ; AlbanyIsland, 3-4 fms. ; Port Molle, coral-reef.DistrUnitlon. Straits of Malacca (Bowerbank).The specimens referred to as being greenish in colour are all dry.