460 American Se ash ells 



in soft coral rocks. Erroneously called c7meifor77iis Spengler which is an 

 Indo-Pacific species (see E. Lamy, 1924). 



Rocellaria ovata Sowerby (Bermuda and the Atlantic Coast, rare) is 

 very similar, but the beaks are at the very end of the valve, and the shell is 

 more elongate. In hians, there is a very small, wing-like projection of the 

 valve in front of the beak. 



Genus Spengleria Tryon 1861 



Similar to Rocellaria, but truncate at the posterior end where there are 

 strong, concentric ribs. Beaks at the anterior third of the shell. 



Spengleria rostrata Spengler Atlantic Spengler Clam 



Southeast Florida and the West Indies. 



I inch in length; valve truncate at the posterior end. There is a very 

 characteristic, elevated, triangular area which radiates from the beaks to the 

 large, posterior end. This area is crossed by strong, transverse lamellations 

 resembling a washboard. Commonly found boring in soft coral rock. Un- 

 common in Florida. 



Superfamily ADESMACEA 

 Family PHOLADIDAE 



Pending publication of the extensive researches on this group by Dr. 

 Ruth D, Turner at Harvard University, we are dividing the groups in this 

 family and treating the species in the conventional manner. 



Genus Cyrtopleiira Tryon 1862 

 Barnea costata Linne Angel Wing 



Figure 94a 



Massachusetts to Florida, Texas and the West Indies. 



4 to 8 inches in length, moderately fragile; pure white in color, but in 

 life covered by a thin, gray periostracum. With about 30 well-developed, 

 beaded radial ribs which are scale-like at the anterior end of the valve. In 

 fresh material, there is a shelly accessory plate over the hinge area. It is 

 somewhat triangular and with complicated furrows. The internal brace 

 under the beaks is spoon-shaped and with a narrow, strongly hooked at- 

 tached end. Common in sticky mud about a foot under the surface (con- 

 sult "Diggin' 'Em Out" by B. R. Bales, The Nautilus, vol. 59, pp. 13 to 17). 

 Some colonies have shells which have pink, concentric stains on the inside of 



