NO. 2183. NEW NORTHWEST AMERICAN BIVALVES— DALE. All 



incremental lines; a rounded ridge extends from the inconspicuous 

 beak to the posterior basal margin, but there is no keel or angle; in- 

 terior distinctly pearly, hinge as in the Atlantic species. Length, 

 5.8; height, 3; diameter, 2 mm. Cat. No. 209912, U.S.N.M. 



Station 4356, 131 fathoms, off Point Loma, San Diego Coimty, 

 California. 



PHOLADroEA SAGITTA (Stearns Ms.). 



Shell closely similar to P. penita Conrad, but with shorter propor- 

 tions, measured longitudinally, and with a corresponding widening 

 of the dorsal appendages of the adult. In all other respects it resem- 

 bles P. pemta, of which it is doubtless a variety. The name having 

 found its way into collections, it was thought best to give it an ac- 

 knowledgable status. The type-specimen comes from Monterey, 

 Cahfornia. Cat. No. 63312, U.S.N.M. 

 65008°— Proc.N.M.vol.52— 17 21 



