Pvn H,i I'UitlS

]50 arcidjE.
and at depths ranging between that mark and 86 fa-
thoms. Glacial deposit, Paisley (Crosskey). Morch
and Walker have recorded it from Greenland, Asbjorn-
sen from Norway, Loven and Malm from Sweden,
M'Andrew from the Spanish coast and Algiers, and I
have fonnd it in the Gulf of Genoa. Gould says that
the N. proximo, of Say (from the Massachusetts coast)
is closely allied to the present species, if not identical
with it ;
but that shell seems to be less glossy, and the
shape rather more obliquely transverse.
My
description, '
note of the animal differs a little from Mr. Clark's
'
and is as follows :— Colour greyish-white.
Mantle finely fringed. Foot tongue-shaped, folded
up when at rest; when it is expanded, it assumes a
roundish-oval shape, and its margin is regularly den-
tate, or set with numerous point-like
tentacles." The
shell is usually less solid than that of A r . nucleus ; the
anterior slope is more abruptly truncate, and the posterior
slope more produced ; the umbonal area is more
convex and prominent; the beaks are more terminal;
and the polished epidermis will always serve to distin-
guish it from its dull congener.
It is not the Area nitida of Brocchi, which is a species
of Leda. Weinkauff supposes that our shell may be the
but this idea is not correct, and I
young of N. sulcata ;
fear that it may
tend to throw some discredit on his list
of Algerian Mollusca, although
he has considerably extended our knowledge of this
it cannot be denied that
branch of the North African fauna, and further results
The
may be expected from his zeal and opportunities.
young of N. sulcata, instead of being smooth and glossy
like N. nitida, is remarkably rough, and of a dusky hue,
and it is a much broader and flatter shell.