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

448 COLLECTIONS FROM MELANESIA.apparently partly formed by upgrowths from short stems placedbeside it, which, though now single, appears to have been originallycompound also ; one surface of this expansion is almost level, buthoneycombed densely with openings with rounded edges, varyingfrom 1 to 4 millira. iu diameter ; the other surface is broken up intoseven more or less pronounced vertical ridges, irregular and frequentlyinterrupted, 3 to 10 millim. in height ; this surface and itsridges are also strongly honeycombed, and between the openingsusually project points and ridges of sponge-tissue. It measures130 millim. (5g inches) in breath, 120 millim. (4^ inches) in height.The second specimen is strap-shaped, 24 to 30 millim. across, somewhatabruptly bent at one point, and terminated by two smaU lobes ;like the other specimen, one surface is comparatively level and ishoneycombed rather minutely (openings "3 to -5 millim. in diameter),while the other is rugose, from the presence of several demi-canals,about 2 to 4 millim. across, which run from the middle to the marginof the frond ; the surface between them is minutely honeycombed anddrawn up into a few sharp points and ridges. The colour is darkishgrey, varying to greenish iu both specimens. The spiculation isessentially that of the above-mentioned form of C. reinivardti, butthe skeleton smooth acuate is only '0003 to '0079 millim. in diameter,and the short, stouter, smooth acuate is wanting ; this slightdifference in spiculation appears to justify the separation of thisform under a distinct varietal name. It is perhaps as nearly relatedto the original form as the first-mentioned specimens. The remarkablefan-shaped specimen appears (having regard to the multiplecharacter of its base) to be made up of several " persons " whichhave united to form a single symmetrical-frond.Ilab. Bird Island, N.E. Australia, coral-reef.78. Clathria frondifera.(Plate XLII. fig. i ; and Part II. of this Ileport, Plate LIII. fig. J.)Halichondria frondifera, Boiverbcuik, Proc. Zool. Soc. 1875, p. 2S8.Amphilectus froudifer, Vosmaer, Notes Roy. Mus. Netherl. ii. p. 115.A very common species, especially in Torres Straits. At firstI was inclined to separate the specimens from Bowerbank'sspecies on account of the greater development of ceratinous substanceinvesting the lines of skeleton-spicules. In the Australianspecimens this occupies from half to two thirds of the diameter ofthe fibres, while in the type specimen from the Straits of Malaccaits place is often almost entirely taken by spicules, and extends tohalf the diameter of the fibre only in some cases. The consistencyof the sponge is hence much tougher and more elastic in theAustralian specimens. The main skeleton-spicules are much stouterin the Malacca specimens.Dr. Bowerbank has omitted to describe a very fine tricurvate fleshspiculowhich occurs both in his specimens and in the present ones.His description is also misleading in not stating, what his own typespecimen satisfactorily exhibits, and what the Australian examples