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NUCULIDAE 3 35
Nucula atacellana Schenck Cancellate Nut Clam
Massachusetts to Maryland.
Figure yoe
Vs inch in length and oval in outline; the cancellate sculpturing is due
to the crossing of numerous radial and concentric threads. Interior scarcely
pearly and with a thick, transparent glaze. Color yellowish brown to lighttan.
Commonly dredged offshore down to 500 fathoms. Formerly known
as N. reticulata Jeffreys and cancellata Jeffreys.
Nucula crenulata A. Adams Atlantic Crenulate Nut Clam
South Carolina to Key West, Florida.
% inch in length, ovate, internal margin finely crenulate. With numerous
concentric, fine ribs which have numerous microscopic crenulations be-
tween them. Interior scarcely pearly; overlaid by a thick, transparent layer
of shell matter, through which radial fractures or lines are discernible; color
yellowish. Dredged in shallow water. Similar in outline to N. tenuis (see
fig. 70c).
Nucula exigua Sowerby Pacific Crenulate Nut Clam
Southern California to Ecuador.
%6 inch in length (5 mm.), shaped hke tenuis and the preceding species.
Concentric rings strong with radial crenulations between. Strongly project-
ing lunular area just under the beaks. Color yellowish. Dredged in shallow
water. Very similar to N. crenulata from the Western Atlantic.
Nucula delphinodonta Mighels Delphinula Nut Clam
Nova Scotia to Maryland.
Figure jod
Vie inch (3 mm.) in length, ovate, fat and smooth except for coarse
concentric growth lines. Anterior end slightly pushed in under beaks and
bordered by slight carination. Ventral edge smooth. Color olive-brown.
9 teeth posterior to and 4 teeth anterior to chondrophore.
Nucula tenuis Montagu Smooth Nut Clam
Labrador to Maryland. Alaska to Lower California.
Figure 70c
Usually %6 inch in length (up to % inch in Alaska), ovate, smooth
except for irregular growth lines. Color a shiny olive-green, sometimes with
darker lines of growth. No radial lines. Ventral edge smooth.