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Show 30 DR. J.S. BOWERBANK ON CEYLONESE SPONGES. [Jan. 7, nating more or less hemispherically, furnished abundantly with large and small defensive and skeleton-spicula projected from all parts of their surfaces at various angles ; large skeleton-spicula flecto-attenuato acuate, stout and strong, usually procumbent on the tubuli; small defensive spicula subflecto-attenuato acuate, incipiently spinous, small and slender. Interstitial spicula the same as those of the skeleton, dispersed, numerous. Sarcode blood-red. I received this very remarkable sponge among the series of specimens from Ceylon, collected by M r . Holdsworth. There is no other genus with which I a m acquainted to which it can be referred but Haliphysema. The only two species known and described are remarkably small, one consisting of a single simple fistulous skeleton, and the other of a ramous fistulous one ; the species under consideration consists of a congregation of numerous single fistulse. Although varying from each other greatly in size, there is a perfect accordance in the principle of their skeleton-structures/all of them exhibiting the tubuliir form, with the distal termination closed and more less dilated, that especially characterizes the genus. There are no distinct indications of any recent attachment of the sponge. The position of its natural base is indicated by the convergence of the skeleton-tubes at their proximal extremities; and it is probable that the specimen had been freely floating about in a living condition for some time before it was taken. There are several large irregular openings on the upper surface of the sponge, which extend deeply into its mass. These orifices have none of the characters of excurrent or cloacal ones. As the internal structures, both in form and mode of disposition, strongly indicate a carnivorous habit in the sponge, it appears highly probable that these large irregular orifices are provided for the double purpose of the admission of water to its tubuli and to allow of the free entrance of minute annelids and other similar prey on which it subsists. The skeleton-tubuli are not closely packed together, and there is frequently a considerable space between them ; and the projection of the defensive spicula from their suifaces maintains this separation from each other, their adherent connexion being accomplished by a loose arrangement of interstitial skeleton-spicula, between which there is ample space for the admission and flow of water amongst the skeleton-tubes. If this reading of their history from their structure be correct (and it is quite in accordance with what we know to occur in other carnivorous sponges abounding in especial organs for the destruction of intruders within their interstitial cavities), the inhalation through the parietes of the tubes will be as in the other species of the genus, and the excurrent streams will take place in their natural positions at the distal ends of the tubes, which project from the surface of the sponge, and form the numerous minute mamillse of the dermal surface. O n fig. 2, Plate VII., representing a single skeleton-tube, near the distal end, at a, there is a minute, rather long and very sinuous tube or skin of what appears to have probably been a slender annelid. |