BRANCHIAE OF THE MUSSEL. 187 



the bouchots were only arranged in four rows ; now 

 however, there are no less than seven rows, and some 

 of them measure more than 1000 yards from the 

 base to the summit. The whole of these bouchots, 

 which were at first limited to the immediate neigh- 

 bourhood of the three villages, of which I have already 

 spoken, extend at the present day uninterruptedly 

 from Marsilly far beyond Charron, and form a gigan- 

 tic stockade for two miles and a half in breadth, and 

 six miles in length. 9 



A curious circumstance connected with the Mytilus 

 remains to be described. Let the reader, who may 

 be so fortunate as to possess a good microscope, cut 

 away a portion of the fleshy part of the Mussel, then 

 place it in a watch glass, and examine it through 

 that 'portal to things invisible/ and, unless I am 

 much mistaken, he will own the sight to be supremely 

 wonderful. Some water being deposited in the glass 

 the fleshy object will be seen to swim about in a 

 most singular and mysterious manner, while a close 

 inspection shows every portion of it to be in active 

 motion. 



This motive power is caused by countless cilia, 

 the rapid vibration of which creates constant currents. 

 This action preserves the health of the poor mollusc 

 by aerating the water which passes over his respira- 

 tory organs. 



That some such wonderful contrivance is adopted, 

 for conveying food within the valves, too, is evident, 



