458 



Ajnerican Seashells 



of dark-brown periostracum. Concentric sculpture of distinct ridges. Color 

 yellowish to brownish white. Uncommon in shallow water. 



Corbula barrattiajia C. B. Adams 



North Carolina to both sides of Florida and the West Indies 



Barratt's Corbula 



Figure 93a 



^ inch in length, moderately compressed, rostrate at the posterior end, 

 with poorly developed or without concentric ridges in the beak area. Right 

 valve slightly larger than the left. The posterior end of the rostrum in the 

 right valve projects far beyond that of the left valve. Color variable: white, 

 pink, mauve, yellow, orange or reddish. Uncommon in shallow water to 

 50 fathoms. 



Figure 93. Corbula clams, a, Corbula barrattiana C. B. Adams, Y^ inch (Atlantic 

 Coast); b, Corbula swijtiana C. B. Adams, ^ inch (Atlantic Coast). Three views 



of each 



Swift's Corbula 



Figure 93b 



Corbula sioipiana C. B. Adams 



Massachusetts to east Florida and the West Indies. 



/4 inch in length, oblong, moderately obese; right valve larger, more 

 obese and overlapping the left valve at the ventral posterior region. Posterior 

 slope in the right valve bounded by 2 radial ridges, one of which is close 

 to the margin of the valve. The left valve has only i ridge. Shell thick, with 

 the posterior muscle scar on a slightly raised platform. External sculpture 

 the same on each valve, consisting of irregular, concentric ridges. Color 



