download pdf

NUCULANIDAE 3 39
About H to % inch in length, shiny green-brown, with prominent concentric
sculpture and characterized by the nearly central umbones. Rostrum
bluntly pointed, slightly upturned at the end. Concentric ribs disappear just
anterior to the carinate border of the dorsal area which is strongly wrinkled.
Adults over K' inch become quite fat. Commonly dredged off southern California
in shallow water. Sorensen reports that this species is found commonly
in fish stomachs off Monterey.
Nuculana penderi Dall and Bartsch Pender's Nut Clam
Forrester Island, Alaska, to Santa Barbara, California.
/4 to % inch in length, moderately elongate, very fat; rostrum short
and pointed; concentric ribs prominent and evenly developed. Dorsal area
of rostrum oval, finely ribbed and bounded by a sharp, smooth, large rib.
Periostracum light-brown. Moderately common offshore.
Nuculana hindsi Hanley Hinds' Nut Clam
Nazan Bay, Alaska, to Costa Rica.
% inch in length, moderately elongate (example: 7.8 mm. long; 4.4
mm. high; both valves 3.0 mm. wide); posterior end rostrate, slightly turned
up at the end. Dorsal area of rostrum smoothish except for faint axial threads
bounded by smooth carinate rib. Sculpture of evenly sized, closely spaced,
distinct, concentric ribs which become obsolete just before the rostral rib.
Exterior light yellowish brown. Interior white with faint pearly sheen. N.
acuta Conrad, a name often given to this Pacific Coast species, has its rostral
rib crossed by concentric ribs. N. penderi Dall and Bartsch is twice as fat,
with a very ovate lunule and is more rounded at the ventral margin. Hanley
in i860 first reported this species from "Gulf of Nicoya, Costa Rica." This
is probably "N. redondo en sis''"' "Burch" \\'oodring 1951. It is dredged commonly
off the West Coast from 1 5 to 600 fathoms.
Subgenus Thestyleda Iredale 1929
Nuculana hamata Carpenter Hamate Nut Clam
Puget Sound to Panama City, California.
Figure z6A
Under % inch in length, moderately compressed, exterior with strong
concentric ribs; characterized by the squarely truncated posterior end of the
long rostrum. Fairly commonly dredged off Californian shores from 20 to
200 fathoms.