287 



'* Proceedings of the Belgian Micro3copican ^^^^ ^^^ Society. 



Society" j 



" Proceedings of the Royal Society of New) 



South Wales" J 



" Report of the Department of Mines, New ) 



South Wales" j" 



" American Naturalist" in Exchange. 



"American MicroscopicalJournal " ... ,, 



" Northern Microsoopist " ,, 



" The Analyst " from the Publisher. 



" Science Gossip " ... ... ... ... „ 



"Grevillea" Purchased. 



Nine Slides The Rev. H. J. Fase. 



Two Slides Mr. W. H. Symons. 



Mr. J. G. Waller read a paper '* On Clionia celata—DoQS the Sponge make 

 the Burrow ? " 



Mr. Priest read a short paper on the same subject. 



At the conclusion of his paper, Mr. Priest remarked that he considered 

 that Mr. Waller had been depending too much upon di'ifid specimens. In 

 the specimen Mr. Waller had spoken of, prepared by him, and showing 

 the round oscula, the membrane had become perfectly dry, and nothing but 

 the spicula were left. He illustrated the manner in which the ScolyUis 

 made its burrow, showing the ramifications with lateral openings for the 

 purpose of depositing its eggs. 



The President then read the following remarks on the subject: — 

 It has been asserted that Cliona has a power by which it bores its habita- 

 tion in rocks and shells, but .what this power is, or wherein it lies, is at 

 present not clearly made known to us. ' Some maintain that the spicula are 

 used as implements by which a burrow is made, while others, ignoring the 

 mechanical theory, believe the boring to be the result of chemical action; 

 but, from the point of view from which I regard the question, I believe that 

 both theories are untenable. In the first place, an examination of the 

 spicules of Cliona will convince the observer that no abrasion has blunted 

 their fine points ; points that terminate sharper than any needle would show 

 at once the effect of wear — but supposing the spicules, being so much harder 

 than the shell or stone in which the boring is made, resist the consequent 

 wear, and maintain their sharpness, by what means can they be so efficiently 

 worked by the small amount of contractility inherent in the sponge's proto- 

 plastic body ? If it is argued, that the continually dropping will in time 

 wear away the stone, and so the continual contraction and expansion of the 

 sponge will in time make its bore into the rock or shell, I would ask how 

 long will it take for a Cliona to form the dendritic growth filling the inter- 

 laminar space of a Pecten-shell, even acknowledging that this growth is the 

 combined product of several CUonce amalgamated ? But the chemical theory 

 is, to my mind, far from conclusive, because it pre-supposes the possession on 

 the part of Cliona of some powerful acid capable of decalcifying shells and 

 limestone, or of dissolving out the silica from flint, such an acid in this 



