672 



PROCEEDINGS OF THE ACADEMY OF 



[Dec, 



lateral at each end of the hinge line, with a deep groove between it 



and the edge of the shell. 



Fig. 6. — Pisidium volutabundum n. sp. 



Alt. 2.56, diam. 1.73, length 3.13 mm. 



Locality. — Pembroke Marsh, near Hamilton, Bermuda; collected by 

 E. E. Vanatta. 



This clam is more truncate than P. abditum Prime with higher 

 beaks and is more orbicular than P. noveboracense Prime. 



Type in the collection of the Acad. Nat. Sci. Phila., No. 100,335. 



