448 American Seas he Us 



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. 



