38 THE president's address. 



under the head of Hymeniacidon Celata of British Spongiadse, I 

 felt that the strength of the evidence rested with the latter, who 

 considered that the excavations in oyster shells were due to 

 annelids, and the sponge developed afterwards. Dr. Bowerbank's 

 description is full of interest, but it is too long, and unnecessary 

 here to be given : my reference is sufficient, and my purpose is to 

 show the reasons for my change of opinion. Being frequently 

 engaged at Torquay, I used my leisure and recreation in researches 

 on the shore. At Anstey's Cove I picked up a fragment of oyster 

 shell having the excavations referred to, but entirely denuded of 

 sponge, and here I found the remains of annelids, or it may be 

 of a larval form analogous. On examination, it became palpable 

 that these, packed together as they were, had entered sub- 

 sequently, and were not the excavators, and this evidently bore 

 upon the subject and suggested that Dr. Bowerbank may have 

 been in some way deceived by appearances. 



At Oddicombe Bay the shore is covered with large rolled pebbles 

 of the limestone underlying the New Bed Sandstone, and these 

 frequently exhibited small cuplike excavations whose diameter 

 rarely came up to the eighth of an inch, but somewhat rhythmically 

 arranged in lines, as if communicating one w^ith another. This 

 appearance was caused by denudation of the surface, as the 

 primitive aperture, where visible, was scarcely larger than tlie 

 prick of a pin. It was a long time before I found any of the sponge 

 preserved, but when I did, I saw that it clearly belonged to the 

 species named by Mr. Hancock as Cliona Northumhrica, and which 

 Dr. Bowerbank denied to be separate from the more common 

 form. This error w^as so great that I doubted if the Doctor had 

 ever seen a specimen, and may have judged from the imperfect 

 illustrations given by Mr. Hancock. I regretted that my means 

 and my time did not allow me to go out dredging, as I have 

 no doubt that at a very short distance from the shore I might 

 have found the living sponge at work. 



Of course the question of the mode of producing the excavations 

 has exercised attention, especially when w^e have to consider that 

 the sarcode of the sponge is soft ; and in my early examinations 

 of the beginnings, it seemed to me that it must have been a hard 

 substance which operated. The suggestion of some solvent seems 

 to be inevitable, and carbonic acid has found favour with many, 

 but it is a matter on w^hich 1 can give no information. On one 



