10 Mr. H. J. Carter on the Suhspherous Sponges. 



longest diameter when fresli. Colour light grej, becoming 

 darker on contraction of the sponge after death. 



Ilab. England, Devon, Budleigh-Salterton beach. Marine, 

 place of growth to me unknown. 



Obs. I found three specimens of this sponge on the beach 

 at Budleigh-Salterton in February last, the largest ol which 

 is about 3 inches in diameter. They did not present any 

 pedicle of attachment, and therefore must have been free for 

 some time previously. Sessile they are most probably at one 

 time or other, and soon cement themselves through the dermal 

 sarcode to loose stones or rocks when they are left in contact 

 with them respectively. But they always fortify themselves 

 with their crust first, which thus as constantly intervenes be- 

 tween the body and the foreign ingredient. It is the dermal 

 sarcode which forms the bond of attachment. Two of the 

 specimens were fresh and living when I found them on the 

 beach ; but of their original place of growth I am as yet ig- 

 norant. Sometimes, probably, such sponges are wrested from 

 their places of attachment by the dredges or trawls of the 

 fishermen as they pass over sandy bottoms, and, when thus 

 loosened and brought to the boat, may not be thrown over- 

 board until some air has got into them, when they float on the 

 surface till this is extricated, but, afterwards sinking, may be 

 drifted at last by under-currents to the shore. 



It is to the microscopic apertures in the dermal sarcode 

 covering the pores and their subjacent cavities that Dr. Bower- 

 bank would apply the terms " pores " and " intermarginal 

 cavities " respectively — points to which we will now more 

 particularly direct our attention. 



GENERAL OBSEKVATIONS. 

 Pores and Oscules. 

 To understand these terms, it is necessary to consider them 

 abstractedly. Thus the young Spongilla growing from the 

 seed-like body may probably be taken as typical of the 

 whole. It consists of many pores and one oscule. The 

 former admit the particles of food to the sponge ; and the 

 undigested portions, having passed through its sarcodal sub- 

 stance (apparently in the same manner and as easily as 

 the undigested particles in Amoebcv are passed through its 

 body, viz. without cicatrix), find their way into the excretory 

 system of canals which terminate in the latter or single oscule. 

 And this system, multijjlicd over and over again as the mass 

 increases in bulk, probably accounts for the great number of 

 pores, together witli the ])lurality of oscules presented by all 

 the larger pieces of sponge. 



