THE president's ADDRESS. 39 



occasion I was on the shore at Teignmouth, after a violent storm, 

 making a gathering of sponges. I found one of a remarkable form, 

 as if covering over in one part a small univalve shell. I made 

 a careful drawing of it, and sent it to Dr. Bower bank for infor- 

 mation respecting it. With that courtesy so eminently character- 

 istic of him, he immediately replied, thanking me, and referred 

 the sponge to his Hymeniacidon Suberea, with an interesting 

 account of its habits, part of which I will give you in his own words. 

 He said, "they have the habit of enveloping shells, and, I may 

 add, that the shells thus enclosed by the sponge are frequently 

 destroyed, so that although, as in your specimen, the form of the 

 shell is strikingly indicated, the substance is so completely absorbed 

 that a needle may be passed through it without resistance." 



Now, it has often occurred to me, that this bears upon the 

 question of solvency in a very direct manner ; and, in subsequent 

 researches, I had a suspicion that this solvent power belongs also 

 to other genera of the sponges. Thus it was that I became 

 convinced of my previously erroneous views, though many details 

 appeared anomalous, entirely aw\ay from our comprehension, as 

 indeed may be said of much more that comes before us in the 

 domain of natural history. Nor is this power of dissolving 

 even confined to the classes alluded to, for, about thirty years 

 ago, it was recorded in the Comtes Rendues, that some of the 

 Polyzoa had the power of boring into shells, and this was first 

 made known by Alceste D'Orbigny, who instituted the genus 

 Teribripora for two boring polyps, which he found in South 

 America ; and M. Fischer had found some of the same family 

 on the coasts of the Gironde and Charente Inferieure. 



It is obvious, therefore, that the habit of boring into calcareous 

 substances is not confined to one class, as it is shown to exist 

 in Fungi, Sponges, and Polyps ; and it appears to me that the 

 suggestion made by KolHker on the Fungi, that the operation 

 might be due to carbonic acid may also be referred to the other 

 organisms to which I have alluded. 



Having thus fulfilled a duty which I considered I owed to 

 myself, as well as to the Club, I now bid farewell to this chair, 

 thanking you all for your courtesy and attention. 



