EOCK-BOREHS. 61 



to support the weight of the frond; and thus the plant is 

 detached and driven on shore by the waves. 



"Ami so the forest tall that groweth, 



Underneath the waters elear, 



Does the little woodman mollusk, 



Level every year; 

 From small causes, great results — 

 Teaching you to persevere." 



HOCK-EORERS. 



The family Pholadm comprises a group of moUusks, the 

 boring habits of which have long been known; they penetrate 

 wood, hard clay, chalk, and rocks, and devastate the labours 

 of man; they attack the hulls of ships, the piles which form 

 the foundations of piers and break-waters, and they force them- 

 selves upon our attention by the loss of property, as well as 

 of life, which results from their hidden depredations. Of 

 this family, those belonging to the genus PJwlas may be more 

 especially likened to the Edomites of Scripture, because they 

 take up their abode in the rock, and hollow out for themselves 

 dwellings therein. With a shell as thin as paper, and brittle 

 as glass, the wonder is how these Rock-borers work their 

 way into and through hard stones. Some naturalists assert 

 that they effect this by means of an acid which decomposes 

 the substance of the rock, and renders it soft; others, that 

 the animal keeps turning round and round like an instrument 

 called an auger, and so gradually rasps away the surface of 

 the stone with the angles of its shell, but we question whether 

 the shell would not be worn out lirst in such a process. 

 The generic name of these "stone-piercers," comes from the 

 Greek word Fholeo — to hide, and the rocky chambers which 

 they hollow out for themselves, are as snug hiding-places as 

 can well be imagined; yet, however deep they may go into these 

 gloomy caverns, as we should be apt to suppose them, they 

 need not be in darkness, for it appears that thc^se Pholades 

 emit a most remarkable light, whether phosphorescent or not 

 does not appear to be determined; so strong is it, that it is 



