MYTTLTJS. 293 



SO arranged as not to be inconvenienced by the opening or 

 shutting of tbe shell. The mouth is singularly defended by 

 a kind of veil, with a double flap on each side, whence the 

 throat descends, like a thread, into the stomach, and close 

 to this appears a curved, brown, and pointed tongue, hnlf 

 an inch in length ; while, on the concave side, is placed a 

 furrow, which the Mussel enlarges or closes, and probably 

 uses in the conveyance of his food. The tongue is sup- 

 posed materially to assist his motions w^hen changing his 

 abode in search of food, or when disturbed by an enemy ; 

 and in the middle of this member, as sentinels to direct its 

 movements, are two bluish spots, which seem to be the eyes. 

 Nor is this all. Another extraordinary contri\ance is dis- 

 coverable. The tongue is provided with a beard, or byssus, 

 fastened by two fleshy roots, and consisting of one hundred 

 undivided parallel lines, an inch in length, of a dark-green 

 tint, having metallic lustre, and terminated by a circular 

 gland, resembling the stigma of many plants. But what, it 

 may be asked, can be the use of such a singular appendage ? 

 x^s the tongue compensates the want of feet, so the byssus an- 

 swers the purpose of innumerable hands. It enables the 

 Mussel to attach himself to rocks and corals, and to adhere 

 when young to the parental shell. It even answers the 



