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Show 14 DR. J. S. BOWERBANK ON THE SPONGIADcE. (^an. ' > largest and best-developed ones the radii occasionally appear very delicately incipiently spinous. These spicula are rather numerously distributed on the membranes. The smaller sphero-stellate ones are not so numerous ; but they are more regular in their forms than the larger ones. The general characters of this species render it not very difficult of discrimination. A few doliolate spicula were found among those separated by the aid of nitric acid; they vary in their forms to some extent: the one figured is the largest I observed. GEODIA DYSONI, Bowerbank. (Plate III.) Sponge massive, sessile ? Surface uneven but smooth. Oscula simple, small, numerous, dispersed rather regularly. Pores inconspicuous. Dermal membrane obsolete. Skeleton somewhat slender and delicate ; fasciculi numerous ; spicula fusiformi-acerate, rather small comparatively. Connecting spicula attenuato-patenti-ternate, rather slender ; radii variable in size. Interstitial membranes-retentive spicula attenuato-stellate, small, and delicate. Ovaria spherical, slightly depressed. Colour in the dried state cream-white. Hab. Honduras (Mr. Dyson). Examined in the dried state. I received a single specimen of this sponge from Mr. Dyson, who found it at Honduras. It has probably been a beach specimen, as nearly the whole of the dermal membrane has been destroyed, and the specimen itself is apparently a portion only of a larger sponge, the under part being quite destitute of dermal crust. The oscula are simple orifices of nearly equal size ; they are found in about equal numbers on all parts of the dermal surface, and they are dispersed at very nearly regular distances from each other. The dermal membrane is nearly all destroyed; but the membranes investing the ovaria in the dermal crust are in a good state of preservation, and so are the interstitial ones, though the sarcode is not very abundant upon them. These conditions of the specimen seem to indicate that the sponge has undergone decomposition to some extent. A few very small fragments of the dermal membrane were detected on the external surfaces of the slices mounted for examination ; they were aspiculous and very translucent; but it is probable that when in a more natural condition it would be found to possess the same spicula as the interstitial membranes immediately beneath the dermal crust, and very likely in greater numbers than in those organs under their present circumstances. The attenuato-stellate retentive spicula are rather abundant on some parts of the interstitial membranes; and a few exceedingly minute radiate spicula were interspersed among them. The skeleton-spicula, compared with many other species of Geodia, may be designated as rather small and slender, and the skeleton-fasciculi delicate in proportion. The connecting spicula are rather |