The GREAT SCALLOP has the power of progressive motion upon the land,
and likewise of swimming on the surface of the water. When it happens
to be deserted by the tide, it opens its shell to the full extent, then
shuts it with a sudden jerk, often rising five or six inches from the
ground. In this manner, it tumbles forward until it regains the water.
When the sea is calm, troops of little fleets of scallops, it is said,
are sometimes to be observed swimming on the waves. They elevate one
valve above the top of the water, which is used as a kind of sail,
while they float on the other, which remains on the surface.