download pdf

448 American SeasheUs
Spisula planulata Conrad Flattish Surf Clam
Monterey, California, to Lower California.
Figure 906
I to 2 inches in length, % as high. Beaks almost at the middle. Anterior
upper margin of the shell sharp-edged and straight. Exterior smooth, yellow-
ish, shiny with the edges commonly stained with rusty-brown. Not very
common. Found from low-water line to 36 fathoms.
Spisula catillijormis Conrad Catilliform Surf Clam
Washington State to Ensenada, California.
Figure 90c
4 to 5 inches in. length, almost as high as long. An oval shell with the
beaks slightly nearer the anterior end. Moderately obese. Dull-ivory, commonly
stained with reddish brown. With numerous, irregularly sized and
spaced growth lines. Periostracum glossy, thin and usually worn off. Pallial
sinus deep, running anteriorly as far back as the middle of the shell. Rather
uncommonly washed ashore. Live specimens rare.
Spisula dolabriformis Conrad Hatchet Surf Clam
Lobitas, California, to Mexico.
Figure 90a
3 to 4 inches in length, rather elongate, compressed and smooth. Poste-
rior end shorter, but more expansive than the rather drawn-out anterior end.
Right valve with the posterior lateral tooth separated into 2 teeth lengthwise
by a long, deep channel. Color a smooth, ivory white, with a dull, light-tan,
thin periostracum. Small gape at the posterior end. Do not confuse with
Mactra nasuta which dips down at the ventral margin, has a shiny periostracum
and a wide posterior gape, nor with Spisula falcata which is similar in
shape, but chalky and with very convex ventral margin to the hinge just
below the chondrophore. Moderately common.
Spisula beinphilli Dall Hemphill's Surf Clam
San Pedro, California, to Central America.
Figure 90b
Up to 6 inches in length, about % as high. Rather obese. Posterior end
more obese and shorter than the downwardly swept, compressed anterior end.
Periostracum grayish brown, dull, coarsely and concentrically wrinkled. The
pallial sinus is moderately deep and inclined upward. Fairly common along
the southern beaches of California.