Page:American Seashells (1954).djvu/546

448 Spisula planulata Conrad Flattish Surf Clam Figure 906 Monterey, California, to Lower California. 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 Figure 90c Washington State to Ensenada, California. 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, com- monly 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 Figure 90a Lobitas, California, to Mexico. 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 periostra- cum 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 Figure 90b San Pedro, California, to Central America. 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.