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

466 COLLECTIONS PROM MELANESIA.spirit-specimen in the present collection is in reality entirely incrusting,though apparently in part erect and cylindrical, owing to itsgrowing along the stem of a Tubularian Hydroid, which is plantedon the back of the crab on which the sponge-growth commenced.In the thicker parts of the sponge the s])icules form long tracts,about 6 spicules in breadth, connected by interdigitation, or byloose, irregularly crossing spicular tracts. The sarcode is subtransparent,somewhat granular, diffusely stained of a reddish-browncolour. The spicules in both the type and the present specimenmeasure about '25 milhm. in length by "0063 millim. in thediameter of the shaft.Hah. Port Curtis, Queensland, 7 fms.Distrihution. " Probably the seas of America " (LamarcJc).HYMENIACIDON.Botverbank, Mon. Brit. Spong. i. p. 191.It appears to me that Bowerbank's genus should be retained forthose sponges with spiculo-fibrous skeleton without horny matter,but in which primary lines are distinguishable, breaking up at thesurface and more or less within the sponge into tufts (thus formingtracts which represent the secondary fibres of llenieridiB), and inwhich there is but one form of spicule, a slender skeleton acuatewith or without indications of incipient spinulation. Such are thecharacters derived from H. canincida, Bowerbank, the specieswhich that author (I. c.) has named as the type of his genus. Itdiffers from Suberites in the absence of distinct spinulation of theskeleton-spicule. Schmidt refers this sponge to Amorphina (Spong.Atl. Geb. p. 76), although he assigns in his diagnosis {op. cit.p. 40) acerate spicules to that genus, which belongs to the familyRenicridfe, whereas Hymeniacidon s. str. is decidedly a Suberitid,closely allied to Stiberites.05. Hymeniacidon caruncula, Bowerhanl-.A broad, horizontally extended specimen from a crab's back ; itpresents a few short mamillfe on its free surface. The form of thespicules and arrangement of the skeleton are fully in accordancewith the type specimens of this British species. The spicules measure-23 to -29 by -0063 to -OOS millim. ; those of the type specimenfrom Tenby, -19 to -32 by -0063 to -008 millim.Ifah. Port Jackson, 5-7 fms.Distribidion.British seas (Bowerhanl-).96. Hymeniacidon agminata.(Plate XLI. fig. E ; Plate XLIII. figs. /, /.)Aggregations of erect, flexuous, more or less compressed stems,8 to 10 millim. in longest diameter, anastomosing; subdividing in a