Pvn H,i I'UitlS

CARDIUM. 279
larger, besides two anterior laterals of unequal size and one
in the left valve two cardinals, the anterior
posterior lateral ;
being much larger than the other, besides a single lateral on
each side all ; the lateral teeth, except the front anterior one
in the right valve, are triangular, and, although short, project
considerably : inside bright and glossy, occasionally iridescent,
and sometimes of a yellow hue and more or less stained with
purplish- or chocolate-brown in front and on the posterior
side, fluted near the margin only : pallia! scar indistinct : muscular
scars oval, large, nearly equal-sized, and deeply im-
pressed. L. 0-55. B. 0-55.
Yar. subquadrata.
Shell rhomboidal, in consequence of the
posterior side being more expanded than usual and of the
dorsal margin being quite straight ; furrows slightly striated,
instead of being punctured.
Habitat :
Oozy ground in the laminarian zone on
most parts of our coasts, at from 3 to 15 fathoms. The
variety is rare, and has onlv occurred to me at Seal-
loway in the mainland of Shetland, and at Sark, one of
the Channel Isles. As an upper tertiary fossil this
species has been noticed by Mr. Grainger at Belfast, by
Mr. James Smith in the Clyde beds at Dalmuir and
Bute, and bv Mr. Godwin-Austen in the Sussex de-
posits. Finmark and Bergen (Sars) ; Sweden, 15-20
fathoms (Malm) ; Cherbourg and Granville (De Ger-
ville) j Vigo (M f
Andrew) ; Gulf of Lyons (Martin) ;
Algeria ( Weinkauff) ; Corsica (Requien) ; Adriatic
(Chiereghini) ; Sicily (Philippi) ; iEgean, 7-30 fathoms
(Forbes) ; and Sebastopol in the Black Sea (Middendorff).
Many intermediate localities have also been
recorded bv other authors.
Turton says that these shells are "sometimes imbedded
in hard clay
:< and both Mrs. Griffiths and ourselves have
taken them from the interior of the hardest stones in
Torbay." They may have found their way
into such
places for the sake of shelter, but (like Sterne's star-