386 ZOOLOGY. 



Family ANATINIDiE. 

 MYTILIMERIA NUTTALLI. 



Mytilimeria nuttalli, Conr. Journ. Acad. Phila. VII, p. 217. pi. 19, f. 5. — Carp. Rep. p. 301. 

 ITab.--&in Diego; Lieutenant W. P. Trowbridge. 



A small group of this curious shell, nestling in a white friable arenaceous substance, was 

 received by the Smithsonian Institution through the kindness of Lieutenant Trowbridge. 



Family PHOLADIDAE. 

 PHOLAS PENITA. 



Pholaspenita,- Com. Jour. Acad. Phila. VII, p. 237, pi. 18, f. 7, 1837. 

 PholMS concamerata, Desuatis, Rev. Zool.p. 234, 1839. — Idem, Mag. de Zool. pi. 17, 1840. 

 Paraphilias penita, CoNR. Jour. Acad. Phila. 1849, p. 2 14, Carp. Rep. p. 290. 

 ffab. — Shoalwater bay. Dr. Cooper ; Straits of P'uca, Dr. Suckley ; Oregon, mouth of Umpqua river. Dr. Vollum, U. S. A. 



"A specimen was obtained from a piece of worn rock which drifted into the bay attached 

 to the roots of macrocystia, the giant seaweed." — C. 



