TELLINIDAE 



4^1 



centric sculpture of fine, irregular threads. Periostracum remaining on the 

 margins is gray. Pallial sinus in left valve runs from the posterior muscle 

 scar anteriorly toward the anterior muscle scar, but does not meet the 

 latter, and then descends posteriorly to meet the pallial line about the middle 

 of the lower margin of the shell. A common cold-water species, distinguished 

 from balthica by its larger size, more elongate shape and pattern of the pallial 

 sinus scar (see fig, 88g). 



Figure 88. American Macomas, showing interior scars, a, Macoiua brota Dall, 

 3 inches (Alaska to Washington); b, M. incongnm von Martens, i inches (Alaska 

 to Washington); c, M. secta Conrad, 3 inches (Pacific Coast); d, M. nasuta Conrad, 

 2 inches (Pacific Coast); e, M. inis Hanley, 2 inches (Pacific Coast); f, M. calcarea 

 Gmelin, 2 inches (Atlantic and Pacific Coasts); g, M. balthica Linne, i inch 

 (Atlantic and Pacific Coasts); h, M. planhisciila Grant and Gale, i inch (Alaska 



to Washington). 



Macoma balthica Linne Balthic Macoma 



Figure 88g 

 Arctic Seas to off Georgia. Bering Sea to off Monterey, California. 



% to 1/4 inches in length, oval, moderately compressed. Color dull 

 whitish, in some with a flush of pink, and with a thin, grayish periostracum 

 which readily flakes off. The shape is somewhat variable. A common inter- 

 tidal and deep-water species. Compare muscle scars with those of calcarea. 



Macoma tenta Say Tenta Macoma 



Cape Cod to south half of Florida and the West Indies. 



