Pvn H,i I'UitlS

CYAMIUM. 261
shaped at the posterior angle, and gradually and slightly curved
on the dorsal side ; umbonal area prominent : beaks blunt and
calyciform, not much recurved, almost contiguous, and often
eroded ; they are placed very excentrically, being close to the
anterior side : ligament cylindrical, horncolour, extending from
the beaks towards the posterior or longer side, and rising above
the level of the dorsal line : hinge- line obtusely angular :
hinge-plate narrow, occupying
rather more than one-third of
the circumference : teeth, in the right valve one extremely
thick and blunt cardinal, which is often bifid or trifid ; in the
left valve two erect and recurved cardinals ; all these teeth
are in adult specimens deeply and beautifully tinged with
purple, and project from under the beaks; laterals hardly
distinguishable from the hinge-plate and apparently forming
part of it : inside glossy, but not nacreous : pallial scar entire :
muscular scars distinct ; the posterior is the larger of the two.
L. 0-07. B. 0-09.
Habitat : Gregarious among
seaweeds and under
stones at low-water mark, and in the laminarian zone,
on sheltered parts of our coasts from Unst to Aldemey.
Mr. Grainger has noticed it in the so-called " alluvial "
deposit at Belfast. This species has a high northern
range,
but its southern distribution is limited. Fabri-
cius, Moller, Morch, and Torell found it in Greenland,
and the last-named conchologist (as w r ell as Steenstrup)
in Iceland ;
Loven and others have recorded it from the
Scandinavian coasts, Recluz and Mace from Cherbourg,
and myself from the Gulf of Spezzia. Stimpson says
that it lives in Massachusetts Bay, " abundantly in June,
about the roots of fuci, which cover the boulders at
Point Shirley."
According to Fabricius this tiny shell has a Greenlandic
name, " Ipiksaunarak." On certain parts of our
coast it occurs in countless multitudes. Mr. Hyndman
shells were contained in the sto-
estimated that 35,000
mach of a single mullet caught in Lame Lough, where
I have noticed them covering the leaves and stalks of