THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SECOND SERIES.] 

 No. 17. MAY 1849. 



XXXVI. — On the Excavating Powers of certain Sponges belonging 

 to the genus Cliona ; ivith descriptions of several new Species, 

 and an allied generic form. By Albany Hancock, Esq. 



[With four Plates.] 



While engaged in investigating the method by which the Mol- 

 lusca bury themselves iu stone, wood, and othei' hard substances^ 

 I was naturally led to examine the chambers inhabited by Cliona ; 

 and having arrived at the conclusion that they are not the de- 

 serted abode of worms, or cavities accidentally formed by erosion 

 or otherwise as has been stated, but that they are worked out 

 by this curious production itself, I asserted such to be the case 

 in a paper communicated by me to the last Meeting of the Bri- 

 tish Association. Since then I have gone more fully into this 

 subject, and as the prevailing opinion appears to be adverse to 

 that expressed by myself, I purpose now giving a detailed account 

 of the facts, which I trust will be deemed sufficient to justify my 

 former statement. 



My investigations have led to the discovery that Cliona celata 

 does not stand alone as an aberrant type, but that it is, in fact, 

 a member of a large group of beings, hitherto almost entirely 

 overlooked, which play apparently a most important part in the 

 oeconomy of nature. I have determined upwards of fifty species 

 of this curious sponge, all inhabiting more or less diversified 

 chambers in calcareous substances, and in other respects well-cha- 

 racterized. Of these species twelve belong to the British seas ; 

 the rest are from various parts of the world. I have ako ascer- 

 tained that Cliona existed during several geological periods, and 

 with the assistance of Mr. W. K. Loftus have determined that it 

 occurs in the crag, in the London clay, in the Paris basin, in the 

 chalk, in the greensand, and in the oolite ; and Mr. Alder has de- 

 tected it in specimens of Pecten Islandicus from a raised beach 

 on the coast of Bute. In most instances the characters of the 



Ann. S^ Mag. N. Hist. Ser. 3. Vol.m. 21 



