Pvn H,i I'UitlS

346 veneriDjE.
cardinal tooth: inside dull chalky-white in the middle and
towards the beaks, with occasionally a slight stain of purple
inside the lips of the lunule ; margin crenulated on the ven-
tral and anterior sides, and more minutely on the inside edges
of the lunule : pallia! scar broad and polished, with a narrow
and tongue-shaped indentation varying in depth, on the posterior
side : muscular scars distinct, triangularly oval. L. 1*15.
B. 1-3.
Var. 1. laminosa. Shell more compressed, and produced on
the posterior side ; ribs fewer and regular ; longitudinal striae
more distinct. V. laminosa, Mont. Test. Brit. Suppl. p. 38.
Var. 2. triangularis. Shell smaller, and larger in proportion
to its breadth.
Var. 3. gibba. Shell more ventricose or tumid and rather
glossy ;
ribs numerous, irregular, and at intervals confluent or
bifurcating on the posterior side.
Habitat : Abundant everywhere on sandy ground
from low-water mark to 85 fathoms. Var. 1. Nearly
equally common; found in Balta Sound between 3 and
5 fathoms and off that coast in the deepest water. Var. 2.
Exmouth (Clark); Tenby and Fishguard (J. G. J.).
Var. 3. West coast of Scotland, and Shetland. This last
variety agrees with the Mediterranean form. Grainger
has noticed the present species in the Belfast deposit,
and Smith in the Scotch " glacial" beds. Steenstrup
has taken it in Iceland ;
it has been recorded by all the
writers on Scandinavian conchology (under the name of
V. striatula), at depths varying from 3 to 70 fathoms,
and by writers on the conchology of other parts of the
European seas, from Normandy to both shores of the
Mediterranean and the Black Sea (under the name ot
V. gallina), at rather less depths. Brocchi and Philippi
have enumerated it as fossil in the Italian tertiaries.
This is not the least of the numerous discoveries for
which we are indebted to Lister. Macgillivray has
justly remarked that it is a very " instructive " species,