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Show 1876.] DR. B O W E R B A N K ON SILICEO-FIBROUS SPONGES. 535 Fig. 3 a, 6 a. Thumb of ditto. 4, 5. View of side and concave surface of suctorial disk of Thyroptera tricolor, Spix. 6. Foot of T. tricolor, with suctorial disk, also calcaneum with projections from its posterior margin. 7. Foot and part of the inferior surface of the leg of Mystacina tuberculata, Forst. 7 a. Thumb of M. tuberculata, showing denticle at base of claw. 8. Foot of Hemidactylus coctcei (Gleckotidse). 9. Hind foot of Hyrax dorsalis. 2. A Monograph of the Siliceo-fibrous Sponges. By BOWERBANK, LL.D., F.R.S., F.Z.S., &c-Part VI. [Received May 31, 1876.] (Plates LVI. & LVTI.) DEANEA FAVOIDES, Bowerbank. (Plate LVI. figs. I, 2.) Sponge laminar or cup-shaped, thin, resembling a thin section of a honevcomb. Surface even. Dermis thin, translucent, aspiculous. Oscula and pores unknown. Skeleton symmetrical, rotulate ; rotulse confluent; fibres cylindrical; central canals large and very distinct. Sarcode dense, opaque, amber-coloured. Colour, in the dried state, dark amber. Hab. West Indies? (Captain Hunter 1). Examined in the dried state. This is a remarkably constructed sponge. It consists of a very open reticulate structure, closely resembling a thin slice of the cells of the comb of the honey-bee taken at right angles to the long axis of the cells. The parietes of these large open areas are constructed of a confluent rotulate rete of the same form as that of the skeleton-structure of Deanea virgultosa, described in the Society's ' Proceedings,' 1875, p. 275 ; and, as in that species, the fibres are all canaliculated and confluent, but the canals are not quite so strongly produced. The external surface and open spaces of the sponge do not appear to be covered with a continuous dermal membrane; but it covers the interstices of the rotular areas of the skeleton rete, and is in those parts thickly coated with a dense and nearly opaque layer of sarcode. The dermal membrane appears to pass inward and to line the interior of the large open spaces of the skeleton-structure ; and in no instance could I find even a fragment of the membranous and sar-codous structures projected into the large open areas of the sponge, although upon their parietes it is in a perfect state of preservation. W e may therefore reasonably infer that in a living state these great orifices are in an open condition. The dermal surface is quite smooth; and a comparatively thick dense stratum of dark sarcode intervenes between the dermal membrane and the siliceous skeleton. I have no certain record of the habitat of this species ; nor a m I cer- |
