Pvn H,i I'UitlS

286 CARDIID.E.
8. C. edu'le *, Linne.
C. edide, Linn. Syst. Nat. p. 1124 ; F. & H. ii. p. 15, pi. xxxii. f. 1-4, and
(animal) pi.
N. f. 5.
Body subglobose, thick, opaque white : mantle pale yellow ;
edges fringed with short white filaments, corresponding with
the ribs of the shell : tithes short, conical, separate at their
bases and divergent, whitish, pale yellow, or reddish -brown,
and sometimes speckled with black; the incurrent tube is
larger than the other, and has its orifice encircled with 10
long white cirri, besides two or three shorter ones between
each the ; excurrent tube has a plain orifice, and is provided
with a distinct retractile tubular valve ; the orifice of each
tube is bordered by a dark or red-brown line, and the sides of
both are clothed with curly white filaments, as well as part of
the mantle, as in other species of Cardium :
gills suboval, pale
brown, finely pectinated ; upper pair much the smaller : palps
longish, pointed, flat, somewhat triangular, red-brown, smooth
on the outer and pectinated on the inner surface : foot long,
and lancet-shaped at the point, proportionally smaller than in
other species, varying in colour from opaque white to pale
yellow or brown, often of a deeper hue towards the extremity.
Shell triangularly rhomboidal, convex, deeper behind,
somewhat compressed towards the margins, and especially at
the sides, very solid and opaque, of a dull hue: sculpture,
24-28 flattish ribs, more or less crested with straight trans-
verse plates, which are stronger and more developed at the
sides ; there are also some extremely fine and microscopical
longitudinal and transverse strire, which cover the whole sur-
face, making it appear partially shagreened ; furrows rather
narrow and slight, without punctures : colour whitish, or yel-
lowish, sometimes light reddish-brown, with a faint prismatic
lustre, marked transversely in the young by zigzag and irre-
gular streaks of purplish -brown : epidermis thin, fibrous, yellowish-brown,
usually rubbed off except round the edges:
margins gently curved but occasionally nearly straight in
front, rounded on the anterior side, obliquely truncate and
wedge-shaped on the posterior side on the ; upper part of this
side the margin forms an obtuse angle with the dorsal line,
which slopes a little : beaks very small, contiguous and con-
sequently often worn by the attrition, considerably incurved ;
* Edible.