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Show 506 DR. J. s. B O W E R B A N K O N [June 15, to the particular species, is apparent-that of allowing a considerable amount of expansion and contraction in the dermal system of the animal, so that, if the skeletons are rigid, the necessary expansions of the dermal organs of the animal may achieve inhalation and exhalation, as necessary to the sponge as to the higher classes of animals, of marine or land-living creatures ; and this is precisely what takes place in the dermal system of Alcyoncellum speciosum, but in a more complicated and beautiful manner than in any other siliceo-fibrous sponge with which I am acquainted. There are several other varieties of form of the remarkably constricted compound floricomous spicula which are figured in the 'Philosophical Transactions of the Royal Society' for 1857, plate xxvii., and also in plate viii. vol. i.' Monograph of British Spongiadae;' but none of these forms are elevated on the distal portion of the shaft of a simple rectangulated sexradiate spiculum, as in Alcyoncellum speciosum. In the portion of the specimen mounted in Canada balsam in the cabinet of Dr. Miller I found a considerable number of gemmules dispersed amidst the tissues ; some were on the skeleton-fibres, while others were attached to the interstitial membranes. They were membranous and aspiculous, closely resembling the same description of organs in Dactylocalyxpumicea, as represented in the ' Philosophical Transactions of the Royal Society' for 1862, plate xxxiv. figs. 17 & 18, and also in ' Monograph of British Spongidse,' vol. i. plate xxv. figs. 340 & 341. They varied in size to a much greater extent than those of Dactylocalyx. The largest one measured ^-^ inch in diameter; another was ^ A J inch in diameter ; and the specimens ranging between these two sizes were comparatively numerous. Others, equally well developed, measured 2 A u incn 5 ana< l^e smallest well-defined one was but -g-g^F m c n m diameter. Thus we have, by the aid of Dr. Miller's beautiful specimen, obtained a much more correct knowledge of tbe anatomy and physiology of this beautiful sponge than we previously possessed ; and, in addition to these interesting facts, a letter published in the * Times' April 30, 1875, from Her Majesty's ship 'Challenger,' contains some interesting information regarding its habits iu its natural state. "The regaderas," as the Spaniards call them, "are found at a depth of about 100 fathoms. The Indian lets down his bamboo arrangement with a strong fine line of Manilla hemp, and pulls it slowly over the ground. Every now and then he feels a slight tug ; and at the end of an hour or so he pulls it in, with usually from five to ten 'regaderas' entangled on the hooks. Euplectella has a very different appearance, under these circumstances, from the cones of glossy network in the British Museum. Its silver beard is clogged with the dark grey mud in which it lives, buried to about one third of its height; and the network of the remainder of the tube is covered with a pall of yellowish fleshy matter, which gives it a heavy look, and greatly diminishes its beauty. The layer of flesh is not so thick as we expected, and only slightly masks the form of even the detailed sculpture of the sponge." |