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

380 COLLECTIONS FROM MELANESIA.millim. respectively ;the vertical height, viz. to base of uppermosttube, is 30 millim. The surface is darkish umber-brown iu colour,that of the body has a slightly irregularly wrinkled parchment-likeappearance, that of the tubes is somewhat wrinkled in the directionof their length, and one of them presents further a somewhatshagreen-like surface, as if beset with very short conuli (scarcely 1millim. high). On dissection it is found that whereas the tubes arechiefly (in the dry state) composed of a horny skeleton, 1-2 millim.thick, the bodj^ is a very cavernous mass whose bulk is largelyoccupied by large canals or chambers, 7-10 millim. wide, openingdirectly into the bases of the similarly wide tubes, the skeleton ofthe body thus consisting of trabecuhe with smooth, rounded surfaces ;the subglobular appearance of the body is produced by the bridgingover of the spaces between these trabeculse by a brown paper-likemembrane, which is found on microscopic examination to containno horny elements, but may or may not enclose a certain quantityof minute foreign bodies (sponge-spicules, &c. ).Examining the skeleton of the body with the microscope, I findfrom vertical sections that it consists of a close reticulation of solid:— cylindrical horny fibres, distinguishable as (1) primary, stouter,approximately straight and parallel to each other, about •07-'04millim. apart, more or less vertical to the surface, according toposition, thickness about •03-"04 millim. ; and (2) secondary, similarto primary, and more or less vertical to them, but often very obliquelyplaced, thickness about -OlS-'OS millim.; distance apart veryvariable, from -14 millim. upwards. Colour of fibre, pale to mediumamber-colour. Although single primary fibres do not appear toproject in the u ay strikingly exhibited in the more typical forms ofEaspongia officinalis, where they project well above the general surface,and where distinct " conuli " are formed by the dermis aroundtheir bases, yet the sections show an aggregation and projection ofthe general skeleton at certain points, apparently representing conuli,but not (in the present state of the sponge) finding expression onthe outer surface in the conical eminences which usually occur herein Easpongia. On the tubes the dermis (immediately below a membranoussubstance containing a few foreign bodies) is formed bya very close and regular horny network, composed of primaryand secondary fibres, like the main skeleton, but arranged parallel,instead of vertically, to the surface. The proportions of the fibresare about the same, respectively, as those of the main skeleton, butthe primaries are only -OS-'l millim. apart. All the skeletonfibresare devoid of sand-core, but are coated (in parts strongly) bythe minute strongly refractive brown globules which Prof. F. E.Schulze has considered to be probably of Cryptogamous affinities.In two points is this sponge of especial interest, viz. (1) in thealmost complete subordination of the general arrangement of theskeletal framework to the largely developed excretory canals ; (2)in the almost total suppression of the "conuli." A further pointis the absence of sand-cored fibres. I was at first inclined to separateit generically from Euspongia, as having the large maeandrine