Pvn H,i I'UitlS

220 kelliid.i:.
middle, produced or wedge-like
and rounded at the anterior
end : beaks broad, blunt, prominent, and contiguous ; they are
placed about two-fifths nearer to the posterior end : hinge-Vine
curved, occupying
rather more than one-fourth of the circum-
ference : cartilage large, yellowish -horn colour, attached to the
shell below the hinge-plate and lodged on an oblique shelf:
hinge-plate very broad, thick, and strong: teeth, in the right
valve two triangular laterals with sharp points, the anterior of
which is a little more raised than the other ; in the left valve
similar laterals, besides a minute cardinal and erect tooth
directly below the beak ; the laterals in each valve lock into
corresponding grooves in the other : inside partially nacreous,
but otherwise of a dull hue ; margin plain : pallia! scar scarcely
visible, but evidently existing on account of the adhesion of
the mantle inside the front margin : muscular scars oval and
distinct. L. 0-85. B. 0-1.
Var. pallida. Shell yellowish -white and nearly trans-
parent, without any tinge of purple
or red.
Habitat : Everywhere in crevices of rocks,
empty cups of Bcdani and among
pygmcea, near high-water mark,
inside the
the tufts of Lichina
and at the roots or
footstalks of CoralYina officinalis and other seaweeds,
sometimes it
and on mussel-beds, between tide-marks ;
is found at depths varying from 3 to 20 fathoms. The
is a Coralline
variety is not uncommon. This species
Crag shell. Steenstrup has found it in Iceland, and
Lilljeborg at Grip in Upper Norway ; but I am not
aware of anv other northern locality. It is widely
diffused southwards from the north of France to the
Canary Isles, and throughout the Mediterranean. Specimens
for which I am indebted to the kindness of
Mr; Cuming (so
renowned for his unrivalled collection
of shells, as well as for the extent of his conchological
experience), and taken by him on the south-western coast
of America, cannot be distinguished from the European
species ; and Dr. Philip Carpenter is of opinion that a
species
from the Gulf of California is the same as ours.