Pvn H,i I'UitlS

200 KELLIIDiE.
occupies the broader side of the shell, contrary
to what
is the usual rule in bivalves and even in this genus, taking
L. squamosum as the type. His remark seems to be
confirmed by the position of the cartilage in the present
species being different from that in L. squamosum. The
characteristic sculptmie of L. nitidum is extremely varia-
ble, but never absent. In apparently the smoothest and
most glossy specimens the pit-marks may always be
discerned near the beaks oculo bene armato. In all
probability Dr. Turton had not used a microscope when
he described the shell to be without punctures. From
this state to that of the variety convexa the gradations
of sculpture are almost endless. The pit-marks usually
are circular, but sometimes they are oval, elliptical,
or polygonal, and occasionally they are confluent and
form undulating wrinkles towards the front margin.
Not unfrequently one half only, or a greater or less por-
tion, of the surface is thus marked, the other part being
quite smooth. Perhaps the most elegant
kind of orna-
mentation is that which combines the impressions exhi-
bited by the first variety with the radiating lines of the
second. The shell may readily be distinguished from
the young of the last species by being much less com-
pressed and comparatively more solid, by
hinge-line being more prominent,
its beaks and
and the teeth in-
finitely stronger and more compact. Mr. Clark says
that it is a far more active creature than L. squamosum,
the shell
creeping up a glass as easily as a Gasteropod ;
is generally carried on one side, with the foot in the
same position, but is sometimes held upright when the
animal is on the march. This little gelatinous mol-
lusk, enclosed in its pellucid valves,
" A liquid prisoner, pent in walls of glass,"
and having the borders of its cloak fringed with tufted