THE BORING MOLLUSCS. 87 



silent molluscs, and all Europe tliouglit that the United 

 Provinces were doomed. Other borers choose rock for 

 their operations ; and many a solid-seeming mass is so 

 perforated by them, that the dashing of a stormy sea 

 may scatter it in fragments along the coast. The fact 

 of boring is familiar enough to every one who has 

 noticed the Eed-nose [Saxicava rugosa) peering from 

 a thousand holes in the hard limestone, and squirting 

 water as it retires on the first application of the ham- 

 mer; but while the fact is undisputed, the source of the 

 animal's power is still an unsettled question. 



How these bivalves bore their way has been a mys- 

 tery, mainly because zoologists have allowed them- 

 selves to be thrown off their balance by contemplating 

 the stupendous results produced by creatures so in- 

 significant. But after learning the history of the 

 formation of coral reefs and islands, we begin to ap- 

 preciate the influence of minute agencies continued 

 through long spaces of time. The Teredo and the Pho- 

 las have no powerful organs, but they have patience ; 

 and as far as I understand the matter, it is clear that 

 the disputes on this subject have been perplexed by 

 the desire to bring forward some organ so powerful 

 as at once to explain the animal's success in boring. 

 Thus the latest writer, M. Aucapitaine,* imagines he 

 explains the phenomenon, by bringing forward the 

 hypothesis of an acid secreted by the animal, which 

 corrodes the rock, or wood, and which is then rasped 

 away by a slow rotatory motion of the shell. The 



* Annates des Sciences Naturelles, 4'™= s^rie, 1854 ; ii. 367. 



