56 CONCHOLOGIST’S COMPANION. 
them open, he relaxes the muscle and expands the 
fringes, which act as wedges, and separate the shells. 
Moreover, every part of this floating pavilion is in- 
laid with a membrane, or epidermis, which, after 
having been saturated with water, unites so closely 
as not to admit the passage of a single drop. 
But what I have always the most admired in the 
Mytilus is, the position of the animal itself, which is 
so placed as not to interfere with the opening or 
shutting of the shell. The mouth is enveloped in a 
veil with a double flap, or lid, on each side, whence 
the throat descends like a thread into the stomach; 
and close to this appears a curved, brown, and 
pointed tongue, half an inch in length; while on the 
concave side is placed a furrow, which the Muscle 
enlarges or shuts up, and most probably uses in the 
conveyance of his food. The tongue is supposed 
materially to assist the motions of the fish, as he 
alters his abode in search of food, or when disturbed 
by an enemy; and in the middle of this member, 
as sentries to direct its movements, are two blueish 
spots, which seem to be the eyes. Nor is this 
all. Another extraordinary contrivance is discover- 
able. The tongue is provided with a beard, or 
bryssus, fastened by two fleshy roots, and consisting 
of one hundred undivided, parallel lines, an inch in 
length, of a dark-green tint with a metallic lustre, 
ee 
