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350 American Seashelh
terior of shell glossy-white with a faint trace of iridescence. Mantle open in
front, and folded at the posterior end into a sessile excurrent siphon. Foot
worm-shaped with a disk-shaped end. Hinge finely dentate.
Crenella faba O. F. Miiller
Arctic Seas to Nova Scotia.
Faba Crenella
Figure 75a
Vi to Y2 inch in length, oval-oblong, with numerous radial ribs. Color
reddish brown. Thin periostracum varnish-like. Byssus golden-brown. Common
offshore.
FiGtJRE 75. Crenella Clams, a, Cre?iella faba Miiller, Y^ inch (Arctic waters);
b and c, Crenella glandula Totten, % inch (New England); d, Miisculus lateralis
Crenella glandula Totten
Labrador to North Carolina.
Say, % inch (Atlantic Coast)
Glandular Crenella
Plate 28); figure 75b, c
% to % inch in length, squarish, with the beaks near one corner. Radial
ribs are fine, numerous, slightly beaded and often crossed by much finer, con-
centric threads. Color olive-brown. A very common offshore, cold-water
species. The smaller decussata has its beaks at the center of its more sym-
metrical shell.
Crenella decussata Montagu Decussate Crenella
Bering Sea to San Pedro, California. Greenland to North Carolina.
Less than % inch in size, oval, with numerous fine, decussated radial
ribs. Color tan to yellowish gray. Dredged from 3 to 150 fathoms. A food
of many marine fishes. Compare with glandula.
Crenella divaricata Orbigny (North Carolina to southeast Florida and
the West Indies) is even smaller than decussata, is pure white, and very in-
flated.