Dr. W. C. Mcintosh on the Boring of certain Annelids. 291 



shell, it absorbs it equally with any other." It will be ob- 

 served that in the last clause he anticipates and answers one 

 of Mr. Lankester's recent queries*. It may also be remarked 

 in passing, that it is probable that the genus {8jpiroglyphus) 

 here referred to is the same as the Stoa of M. Marcel de Serres, 

 as hinted by Mr. Shuttleworth in the same vol. of the ^ Ann. 

 des Sc. Nat.' 



This chemical or solvent theory has been shown by many 

 authorities to be inadequate to explain all the facts connected 

 with the boring of the Mollusca ; for, besides the boring of 

 wood by the Teredo ^ some of the Pholades perforate gneiss, 

 mica-schist, talc, peat, resin, and sandstone, as well as calca- 

 reous rocks ; and I would only refer to the careful digest and 

 observations on the subject in the ^ British Mollusca ' of Messrs. 

 Forbes and Hanley, and to the experienced and recent re- 

 marks of Mr. Gwyn Jeffreys f. M. Valenciennes is of the 

 same opinion with regard to the Echini. Indeed MM. Cail- 

 liaud X and Fischer §, in describing the borings of E. lividusj 

 show that it excavates (notwithstanding the adverse opinion 

 of Mr. Trevelyan |1) not only calcareous rocks, but gneiss, 

 granite, whitestone (leptynite), schist, &c., while foreign spe- 

 cies invade basalt : and the former author, in his first plate, 

 represents several specimens of Echinus lividus, of the natural 

 size, located in their holes in granite from Croisic, on the coast 

 of France. Dr. BowerbankU likewise, in his careful and con- 

 scientious observations on the boring question, gives no sup- 

 port to such a theory ; and Mr. Hancock ** could find no trace 

 of acid in his specimens of Cliona. M. de Quatrefages adds 

 his weight into the scale against the idea of a solvent in the 

 Annelidan perforations. Lastly, although Mr. Lankester ap- 

 pends the following sentence to his letter in the ^ Annals ' 

 for July last, " It is almost impossible to assign any but a 

 chemical means of excavation to BonelliaJ'' it may be re- 

 marked that M. Lacaze-Duthiers, in the original paper, appears 

 to be more cautious than to attribute its work to such an 

 agency. 



Physiologically it cannot be considered that carbonic acid in 



* Ann. Nat. Hist. ser. 4. vol. i. p. 237, line 9 from bottom. 



t Brit. Mollusca, vol. i. Introd. p. xxvii, and vol. iii. p. 94. 



X Catalogue des Rad., des Ann^L, des Cirrliip. et des Mollusques Manns 

 &c. dans le Depart, de la Loire Inferieure : Nantes, 1865. 



§ Ann. des Sci. Nat. Zool. s6r. 5. torn. i. 1864, p. 321. 



jl This gentleman considered that the animal {JE. lividus) possessed 

 neither chemical nor mechanical power of perforating rocks, out that 

 such excavations were produced by coimtless generations of such creatures, 

 which thus, after the lapse of ages, graduallv had worn the stone away. 

 (Edinb. Phil. Journ. vol. xlvi. 1849, p. 386.)"' 



5[ British Spongiadse, vol. i. p. 221. 



** Ann. Nat. Ilist. fcer. 2. vol. iii. p. 329. 



