Pvn H,i I'UitlS

AXIXUS. 251
much more recurved; and the tooth-like folds are
stronger and more prominent. I at one time thought
it might be the young of A. Sarsii ; but having been
favoured bv mv kind friends in the North with a series
of specimens from several localities, I am enabled to
express a positive conviction that my shells are not the
The shell of A. Sarsii
young of that species or variety.
in all states of growth is even more globular than A.
flexuosus, the furrows are equally strong (except in
large specimens, when they are less conspicuous), and
the tooth-like folds are wanting or indistinct. A. Sarsii
is usually found in deeper water than A. flexuosus, and
I am not aware that both forms have ever been taken
together. Asbjornsen gives different localities for each
on the coast of Norway ; and Malm informs me that
on the Swedish coast he always finds A. flexuosus on
softer ground and in shallower water than the other.
A. Sarsii attains a much larger size ; and Lilljeborg
showed me a comparatively gigantic specimen, which
was upwards of an inch long. It occurs in the Udde-
valla beds. The authors of the '
British Mollusca '
advertently placed A. Croulinensis with A.ferruginosus.
The outline of each will be sufficient to distinguish
them, independently
in-
of other characters. The shell of
the former is obliquely oval, and that of the latter
almost globular.
3. A. ferrugixo'sus*, Forbes.
Kellia ferruginosa, Forbes, iEgean Invert., Brit. Assoc. Rep. 1843, p. 192.
Lucina ferruginosa, F. & H. ii. p. 60, pi. xxxiv. f. 1 .
Shell nearly globular, but more tumid towards the beaks,
covered with a thick ferruginous crust or coating like the rust
of old iron, beneath which it is thin, opaque, and rather glossy :
* Covered with iron-rust.