74 THE SEA-SIDE AND AQUAKIUM. 



accidentally overturned the big Pholas' shell, and there 

 lay the little Blenny quite dead, after the fashion of 

 the hapless Genevra. Whether his own weight, 

 when inside, had toppled over the shell, or whether 

 it resulted from a chance collision against a larger 

 Blenny, or some other animal, I cannot tell. Suffice 

 it that Little Jock was defunct. 



"We must now return to the consideration of those 

 points regarding the Pholas that impart to it its 

 peculiar and mysterious character; namely, the mode 

 in which it perforates the rock which serves alike as 



" Its dwelling and its sepulchre." 



Mr Sowerby, in his pleasant " Manual of British 

 Conchology," devotes an entire chapter to this sub- 

 ject, from which I take the liberty of making the 

 following quotation, which will serve to bring the 

 matter vividly before the mind's eye of the uninitiated 

 reader: 



" Professor Forbes thus ably sums up the various 

 theories which have been promulgated on this very 

 interesting and difficult point : ' They may all be 

 classed under five conclusions: 1st, That the boring 

 mollusca perforate by means of the rotation of the 

 valves of their shells, which serve as augers; 2d, 

 That the holes are made by rasping, 'effected by 

 silicious particles studding the substance of certain 

 parts of the animals ; 3d, That currents of water, set 

 in action by the motions of vibratile cilia, are the 

 agents; 4th, That the animal secretes a chemical sol- 



