the usual and natural state of the shell is that of being kept open 
for a little distance, to allow the water necessary for its nourish¬ 
ment and respiration to flow in and out; but as a security against 
danger, it was necessary to furnish the animal with the means of 
rapidly closing the shell, and retaining the valves in a closed state. 
These actions being only occasional, yet requiring considerable 
force, are effected by means of a muscular power, for which pur¬ 
pose one or two, or sometimes more, strong muscles arc placed 
¥ 
between the valves, their fibres passing directly across from the 
inner surface of one to that of the other, and firmly attached to 
both ; these are called the abductor muscles, because their office 
is to draw or pull. IIow strongly they do this, those whose busi¬ 
ness it is to open oysters can best tell. If the animal within were 
not alive, the process, of course, would not be a difficult one, as 
in that case the muscles would be relaxed and the shell would 
come open of itself. The two portions of the shell are joined to¬ 
gether by a hinge, it is mostly formed by the teeth of one valve 
inserting themselves between those of the other, or by the teeth 
of one valve fitting into the cavities or sockets of the opposite 
one. Upon the number and relative situation of the teeth princi¬ 
pally depend the specific distinctions. When hinges have no 
visible teeth they are termed inarticulate, as the oyster. The 
hinge of the oysters is formed of the inner layer of the shell, and 
strengthened by a ligament which is wonderfully elastic. When 
the shell is drawn together by the abductor muscles, the ligament 
is at full stretch, and as soon as they relax at all, it contracts, and 
causes the shell to gape. This process is repeated as often as 
may be necessary for the safety and sustenance of the animal 
within, whose mouth is situated at the narrowest part of its habi¬ 
tation—namely, near the joint of the hinges which connects its 
upper and under shell*. Truly the oyster may be considered the 
monarch of bivalves. His palace, to be sure, is somewhat rough 
and rugged outside, but within, its walls are smooth and polished, 
lustrous and iridescent, and altogether beautiful, of a nacreous or 
pearly appearance, now flushing into a, rose tint, now fading into 
a pure white, and adorned sometimes with goodly pearls of price. 
Truly this monarch of the conchifers has a habitation worthy of a 
prince, wherein he lives in right royal state. You may smile, 
