Pvn H,i I'UitlS

196 KELLIID.E.
This curious shell was discovered by Montagu, and
described by him from a single valve. Although quite
aware that it did not belong to any of the Linnean
genera,
he was much more averse than naturalists of the
present day to travel out of the beaten path,
and he
therefore provisionally placed it in Solen. Its shape is
not very dissimilar from that of a Solenicurtus. Its
nearest comparison, however, would be to a fish-scale ;
and its sculpture is equally beautiful, and resembles the
finest Jace laid out on cambric. The pit-marks which
cover the surface of the shell are like those which ladies
so often see on the top of their thimbles, but without
admiring or noticing the ornamentation, their thoughts
perhaps being occupied with something
else. The re-
fraction of light through the punctures makes the silver-
white shell appear under a microscope to be studded
with glittering dew-drops. Nor is the animal less
curious or lovelv than the shell. Two excellent ob-
servers, Alder and Clark, have published some interesting
details of its peculiarities and habits. Mr. Alder says
that the single filament noticed in my description is
waved to and fro like a tentacle when the animal is
crawling, and apparently enables it to feel its way
as it
goes. The other filaments are comparatively motionless,
floating loosely in the water, though capable of being
thrown out or withdrawn at pleasure. The edges of its
large foot can be either closed or expanded so as to
form a disk, as in Nucula. As may be imagined from
the size of the foot, the Lepton crawls about very freely ;
and sometimes it swims in an inverted position on the
under surface of the water,
teropods, the hinder part of the foot being
in the manner of some Gas-
then unfolded
and disk-shape ; but its favourite posture is that of
repose, suspended perpendicularly,
with the beaks of its