Pvn H,i I'UitlS

SCROBICULARIA. 445
rounded on the anterior side, truncate or bluntly angular on
the posterior side, which is obscurely angulated and has a decided
gape, nearly straight on each of the dorsal sides, which
form by their junction with the beaks an angle of from 60 to
70 degrees : beaks very small and calyciform, inclining a very
little, if at all, towards the posterior side umbones ; projecting
: ligament rather long and continued between the beaks
to the anterior side, dark horncolour : cartilage large, bent
like one of the knee- timbers of a ship, yellowish -brown : hingeline
: obtuse-angled hinge-plate thick, short, broad in the mid-
dle and tapering gradually to each side : teeth, in the right
valve two thin, laminar, nearly parallel cardinals, the anterior
in the left
being mostly higher but shorter than the other ;
valve a straight laminar cardinal which is often double the
;
sides of the hinge-plate are callous or ridge-like, and serve the
purpose of lateral teeth in keeping the hinge more securely
closed : inside polished and somewhat nacreous, minutely and
indistinctly striated lengthwise, and microscopically fretted like
seal-skin ; margin bevelled and : sharp-edged pallial scar distinct,
with a large triangularly oval sinus, as in S. tenuis, but
more rounded :
having the upper angle m
uscular scars rather
deep, of an irregular shape, anterior oblong, posterior trapezoidal.
L. 1*5. 3. 2.
Habitat :
Beds of mud and clay, at low-water mark,
and as deep as 4 fathoms seawards, on all our shores
from Exmouth (Clark) to Aberdeen (Macgillivray), as
well as in Ireland and the west of Scotland :
it is gre-
garious. Fossil in a raised sea-bed at Swansea discovered
in the course of excavating the South Docks (Moggridge)
; similar deposit at Belfast (Hyndman and Grain-
ger) ; York and Forth beds (Smith) ; Sussex tertiaries
( Godwin- Ansten). Scandinavian coasts from Bergen to
Kiel Bay, France from Boulogne to Nice, Vigo and
Malaga, Algeria, Spezzia, Naples, and Sicily.
The name of this species may have been derived from
the peculiar flavour of the animal. Montagu says that
it has an extremely bitter taste— although the old pro-
verb occurs to one's mind when we learn from Capel-