14 DR. J. S. BOWERBANK ON THE SPONGIAD.E. [Jail. 7, 



largest and best-developed ones the radii occasionally appear very 

 delicately incipiently spinous. These spicula are rather numerously 

 distributed ou 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 1 Surface uneven but smooth. Oscula 

 simple, small, numerous, dispersed rather regularly. Pores incon- 

 spicuous. Dermal membrane obsolete. Skeleton somewhat slender 

 and delicate ; fasciculi numerous ; spicula f usiformi-acerate, rather 

 small comparatively. Connecting spicula attenuato-patenti-ternate, 

 rather slender ; radii variable in size. Interstitial membranes — reten- 

 tive 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 preser- 

 vation, 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-fas- 

 ciculi delicate in proportion. The connecting spicula are rather 



