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Show 1869.] DR. J. S. BOWERBANK ON SILICEO-FIBROUS SPONGES. 325 illustrations to my paper *•** On the Anatomy and Physiology of the Spongiadee" (Phil. Trans, for 1862, plate 34. figs. 17 & 18), and also in vol. i. of 'Monograph of British Spongiadse' (plate 35. figs. 340 & 341). The latter figure in each of these quotations represents one of the gemmules filled with granular matter, x 666 linear. A small portion of the skeleton from the Porto Rico specimen is also figured in Plate X X I I . fig. 1, of the present work, x 108 linear, to exhibit the abundance of these organs in situ. In this portion of the skeleton (fig. 1, Plate X X L , representing the general contour of the skeleton) the gemmules are very few in number, the original of the figure being from a different portion of the sponge. IPHITEON BEATRIX, Bowerbank. Aphrocallistes beatrix, Gray, Proc. Zool. Soc. 1858, p. 115, pl.xi. Sponge fistulous, branching irregularly. Surface of the rigid skeleton undulating or tuberous. Oscula congregated, terminal. Pores and dermal system unknown. Skeleton symmetrically radial ; radii -short and stout; areas of the rete mostly six-sided, spaces within triangular ; fibre cylindrical; central umbo of the areas spinous. Inhalant spaces of the skeleton-surface armed with stout elongo-conical, acutely terminated, and abundantly spinous defensive fibres. External defensive spicula of the skeleton acerate, distal portions incipiently recurvato-spinous, long and slender, very numerous ; and also stout sub fusiformi-cylindrical, entirely spinous spicula, few in number. Interstitial spicula attenuated rectangulated hexradiate, large and small; axial ray of the latter occasionally spinous at one or both of its terminations; spines very long and slender, curving towards the extremities. Spicula of the membranes:-Tension-spicula acerate, very slender. Retentive spicula acerate, verticil-lately spinous ; verticilli few in number; spines large and acute, and also porrecto-spinulo-multiradiate spicula with slightly attenuated shafts; radii from three to six or more, slender and minute, few in number. Gemmules spherical, membranous, irregularly dispersed. Colour in the living state unknown. Hab. Malacca (Admiral Sir Edward Belcher). Examined in the skeleton state. Dr. Gray's description of this beautiful sponge in the ** Proceedings' of this Society for 1858 is inaccurate in several important points. Iu the first place he describes it as calcareous, whereas it is purely siliceo-fibrous. H e also states the outer surface to be " formed of intertangled transparent spines which inosculate and unite with each other at the intersection," while the whole of the skeleton is formed of a symmetrical network of siliceous fibre. H e further states that " the end of the main tube is closed with an open network formed of spicula," when in reality it is an intricate reticulation of siliceous fibre of a very remarkable structure. Subsequently the author writes, "in this genus the mass of the sponge is formed of small spicula, which inosculate and are united together, forming a hard mass pierced with numerous closed, small, uniform PROC ZOOL. Soc-1869, No. XXII. |
