350 



American Seashelh 



terior of shell glossy-white with a faint trace of iridescence. Mantle open in 

 front, and folded at the posterior end into a sessile excurrent siphon. Foot 

 worm-shaped with a disk-shaped end. Hinge finely dentate. 



Crenella faba O. F. Miiller 



Arctic Seas to Nova Scotia. 



Faba Crenella 



Figure 75a 



Vi to Y2 inch in length, oval-oblong, with numerous radial ribs. Color 

 reddish brown. Thin periostracum varnish-like. Byssus golden-brown. Com- 

 mon offshore. 



FiGtJRE 75. Crenella Clams, a, Cre?iella faba Miiller, Y^ inch (Arctic waters); 

 b and c, Crenella glandula Totten, % inch (New England); d, Miisculus lateralis 



Say, % inch (Atlantic Coast) 



Crenella glandula Totten 



Labrador to North Carolina. 



Glandular Crenella 



Plate 28); figure 75b, c 



% to % inch in length, squarish, with the beaks near one corner. Radial 

 ribs are fine, numerous, slightly beaded and often crossed by much finer, con- 

 centric threads. Color olive-brown. A very common offshore, cold-water 

 species. The smaller decussata has its beaks at the center of its more sym- 

 metrical shell. 



Crenella decussata Montagu Decussate Crenella 



Bering Sea to San Pedro, California. Greenland to North Carolina. 



Less than % inch in size, oval, with numerous fine, decussated radial 

 ribs. Color tan to yellowish gray. Dredged from 3 to 150 fathoms. A food 

 of many marine fishes. Compare with glandula. 



Crenella divaricata Orbigny (North Carolina to southeast Florida and 

 the West Indies) is even smaller than decussata, is pure white, and very in- 

 flated. 



