PHOLAS MUSSEL COCKLE. 87 



somewhat damaged for our purpose. But if inanimate 

 creation can teach lessons of wisdom to man, few, we 

 think, will be disposed to deny, that a fragment of 

 perforated rock is more forcibly eloquent upon the 

 subject of perseverance under difficulties, than the 

 most nervous appeals to the mind from the pen or 

 lips of any human philosopher." 



The Common Mussel (Mytilus edulis) should 

 always have a place in the Aquarium. It is a very 

 hardy creature, and although familiar to every one, is 

 by no means an uninteresting object of contemplation. 

 It especially commands our admiration, whenever, by 

 means of its byssus (formed by a number of silk-like 

 threads), it anchors itself to the sides of the tank, 

 becoming so fixed that it would take pretty consider- 

 able force to dislodge it. 



COMMON MUSSEL (shewing the Byssus threads). 



" The manner in which the byssus is accomplished is 

 as follows : a deep groove runs along the under surface 



