Pvn H,i I'UitlS

CRENELLA.
135
muscle which connects the terminal lobe with the basal
attachment of the foot to the body. While the animal
is crawling a tremulous movement is seen to pervade
the lobe. The stalk and sheath are faintlv wrinkled
across. The foot is protruded from the ventral opening
in the mantle, and extends in a direction opposite to
that of the beaks.
Col. Montagu described and established this species
from a single valve, which was found by his friend
Capt. Laskey at Dunbar; but he erroneously supposed
it might be the Mytilus faba of Miiller. It is the
Modiola cicercula of Moller, but not the M. glandula of
Totten, which latter species (as Sars has remarked) is
more rhomboidal and broader, besides being three or
four times the size of our shell. C. glandula and C.
faba are more nearly allied. The Mytilus
Lamarck is a large South American mussel.
decussatus of
Two specimens of C. faba were procured some years
ago by Professor King from the stomach of a wild duck
that was shot near Newcastle ; and one of them is in
my
collection. This shell is common in the arctic zone
on both sides of the Atlantic. The bird may have picked
up the shells in upper Norway or Iceland ; and better
evidence is wanting before C. faba cau be admitted into
the British fauna.
Another species, however, of a much more novel and
interesting kind has been takemon our northern coasts
under similar circumstances. During the severe winter
of 1855 several birds of passage were killed near Scar-
borough. One of them came into the possession of
Mr. Alfred Roberts, an intelligent bird-stuffer, who
found a number of small shells in its crop. These he
gave to Mr. Bean, and they proved to be the young of
Mytilus edulis and Littorina litorea, and an unknown