(_Anomia ephippium_.)
The shells of the Anomiæ are exceedingly irregular in their form;
like the oysters, they remain during the whole of their existence
attached to one spot, either on a rock, or on the shell of some larger
inhabitant of the deep. These shells are more frequently found in the
same places as the oyster, and very commonly attached to the shell of
the latter; as an article of food, the Anomia is of little or no value.
Its organization and manner of living are much the same as those of
the oyster. The most singular part of its construction consists in
the use made of one of the muscles with which it is furnished, which,
instead of being attached to the shell, is fixed to a solid piece of
shelly substance, in the form of a cone with the top cut off; this
_operculum_, or lid, closes a singular opening in one of the valves of
the shell itself. The animal adheres to the rock, or other substance,
by means of this lid, and is detached with great difficulty.
[Illustration: _Anomia ephippium._ [_Anomia_, a little bowl;
_ephippium_, a horse’s foot.]]