Pvn H,i I'UitlS

350 VENERID^.
and the same numerous microscopical striae which have been
already noticed in several species of Venus : colour yellowish-
white with a golden tint, mostly variegated by several broken
rays, or marbled with zigzag streaks or blotches of reddish-
brown or light purple, sometimes of a uniform pale yellow or
milk-white: epidermis horny, usually retained only on the
lunule and corselet : margins obliquely rounded in front, and
more sharply curved on the anterior side, produced or wedgeshaped
at the posterior end, which is also curved with a gradual
and rounded slope on the dorsal or ligamental side: beaks
umbonal area ra-
small, slightly recurved, and close together ;
ther : prominent lunule lanceolate, not deep but distinctly excavated
and denned by a separating line or groove ; it is usually
stained with purple or of a darker hue than the prevailing
colour ; the lips do not project : corselet narrow and indistinct,
sculptured in the same way but not so strongly
as the rest of
the shell : ligament rather narrow, yellowish-brown, wholly exposed,
contained in a groove between the dorsal margin and
the hinge-line, which is obtusely angular: hinge-plate short,
thick, and flexuous : teeth, in the right valve three cardinals,
of which those in the middle and on the anterior side are
erect, double, and but slightly divergent, and the posterior
is smaller and triangular ; the left valve has the same number
of cardinals, but the smallest is on the anterior side, and the
other two are erect, double, and nearly straight ; laterals on
the anterior side sunken but distinct: inside rather glossy,
tinged with orange and often having a purple stain at the
sinuous on
hinge : pallial scar broad and iridescent, deeply
the posterior side : muscular scars triangular, large, and deep.
L. 1-3. B. 1-5.
Var. 1. quadrata. Shell compressed, and having a squarish
outline owing to the dorsal margin being straighter.
Var. 2. ovata. Shell more compressed and produced at
each end.
Habitat : Southern and. south-western coasts of
England and Ireland, as well as the Channel Isles, in
sandy gravel,
at from 3 to 18 fathoms. Cullercoats and
Whitburn (Alder, fide J. H. F. and Abbes) ; Tenby
(Lyons) ; Pwllheli (M'Andrew) ; Belfast (Hyndman) ;
Lough Strangford (Dickie) ; Clyde district (Smith and
others) ; Jura Isle (Bedford). It occurs in a fossil state