download pdf

CARD]IDAE 403
round and slightly gaping at the posterior end. Exterior brownish gray
and may be with brown, concentric rings of growth. Interior dull-white.
Beaks inflated and high. Ligament large and strong. No lunule or escutcheon.
Weak radial ribs seen at both ends only. Concentric growth ridges promi-
nent near the margins. Muscle scars and pallial line deeply impressed. Foot
of animal large and suffused with heavy, red mottlings. Very commonly
dredged in cold, northern waters.
Genus Clinocardium Keen 1936
Clinocardhim ciliatuvt Fabricius Iceland Cockle
Greenland to Massachusetts. Alaska to Puget Sound, Washington.
Plate 320
1/4 to 3 inches in size, a little longer than high, with 32 to 38 ridged
radial ribs which are crossed by coarse concentric lines of growth. Exter-
nally drab grayish yellow with weak, narrow, concentric bands of darker
color. Interior ivory. Periostracum gray and conspicuous. Especially abun-
dant from Maine northward in offshore waters.
Clinocardium nuttalli Conrad Nuttall's Cockle
Bering Sea to San Diego, California.
Plate 31b
2 to 6 inches in length; smaller ones being almost round, adults tending
to be higher than long; moderately compressed; commonly with 33 to 37
coarse radial ribs which are creased by half-moon-shaped riblets. Older
specimens worn smoothish. Exterior drab-gray, with a brownish yellow,
thin periostracum. Common offshore. Once called C. corbis Martyn. Known
locally as the Basket Cockle.
Clinocardiimi fucanum Dall Fucan Cockle
with 45
Sitka, Alaska, to oif Monterey, California.
I to 1/4 inches in length, longer than high, moderately inflated, and
to 50 low, poorly developed, radial ribs which are crossed by mi-
croscopic concentric lines. No wavy, radial furrow on the upper posterior
edge of the shell. Color whitish with a grayish-brown periostracum. Common
in the Puget Sound area.
Young C. nuttalli are distinguished from this species by their 2 first ribs
behind the ligament which are large, rounded and make a wavy edge to the
shell. In small specimens of C. ciliatmn, the top edges of the ribs are sharp;
in jucanuvi they are rounded.