Dr. W. C. M‘Intosh 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 (Spiroglyphus) 
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 Se. 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 Zeredo, some of the Pholades perforate gneiss, 
mica-schist, tale, 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 Jeffreyst. M. Valenciennes is of the 
same opinion with regard to the Hchini. Indeed MM. Cail- 
liaud ¢ and Fischer §, in describing the borings of HZ. lividus, 
show that it excavates (notwithstanding the adverse opinion 
of Mr. Trevelyan ||) 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 F rance. Dr. Bowerbank{ 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 Bonellia,” 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. 
+ Brit. Mollusca, vol. i. Introd. p. xxvii, and vol. iii. p. 94. 
{ Catalogue des Rad., des Annél., des Cirrhip. et des Mollusques Marins 
&e. dans le Départ. de la Loire Inférieure : Nantes, 1865, 
§ Ann. des Sci. Nat. Zool. sér. 5. tom. i, 1864, p. 321. 
|| This gentleman considered that the animal (E. lividus) possessed 
neither chemical nor mechanical power of perforating rocks, but that 
such excavations were produced by countless generations of such creatures, 
which thus, after the lapse of ages, gradually had worn the stone away. 
(Edinb. Phil. Journ. vol. xlvi. 1849, p- 386.) 
{| British Spongiadze, vol. i. p. 291, 
** Ann. Nat. Hist. ser. 2. vol. i. p. 329. 
