Pvn H,i I'UitlS

circe. 323
ridges, of a somewhat irregular width, the interstices or
furrows being very narrow and slightly impressed ; the surface
is also covered with minute and irregular intermediate stria? :
colour from milk-white to rich purple, through all the shades
of j^ellow, brown, and red, often variegated or relieved by
diagonal streaks or rays of some one of those tints, and inter-
a common
spersed with spots, or lineated in a zigzag pattern ;
arrangement of these varied hues consists of two streaks of a
darker or lighter reddish-brown radiating from the beaks at
an acute angle, one towards each side, and resembling an inverted
V the ; colouring is so diversified, that it is almost im-
possible to describe it : epidermis semitransparent,
of varnish : margins
like a coat
semicircular in front and at both sides,
for at least half of the circumference, straight on the upper
part of the anterior side below the beaks, and sloping either
abruptly or with a gentle curve on the dorsal side to the posterior
angle: beaks regularly but not much recurved : lunule
not deep, denned by an impressed line : corselet : slight ligament
short, horncolour half of ; it is visible outside, and the
base rests on a groove excavated within the dorsal : margin
hinge-line rounded : hinge-plate thick, and somewhat flexuous :
teeth, as in the description of the genus ; the two cardinals in
the right valve on the anterior side are shorter and thicker
than the other on the posterior side, which is laminar and
in the left valve the middle
nearly parallel to the dorsal line ;
cardinal is the shortest and thickest, that on the anterior side
is much smaller than the rest, and the tooth on the posterior
side (which is double) corresponds with the laminar tooth in
the right valve ; laterals short and strong, the inside tooth in
the left valve being considerably smaller than the other:
inside polished and slightly nacreous, sometimes tinged with
neshcolour ; margin bevelled and smooth, but occasionally in
the left valve it is indistinctly crenulated: scars not very
distinct. L. 0*55. B. 0*6.
Var. triangularis.
Shell acutely triangular, in consequence
of the beaks being more prominent and the sides more truncate.
Venus triangularis, Mont. Test. Brit. p. 577, tab. 17. f. 3.
Habitat :
All our coasts, on a sandy or nullipore
bottom, in 5-85 fathoms. The variety lias been found
by Montagu and myself
in Falmouth Harbour. This
species occurs in the Red and Coralline Crag. Sars