452 



CALIFORNIA ACADEMY OF SCIENCES 



[Proc. 4th Ser. 



1865. ? Mopalia sinuata Carpenter, Proc. Acad. Nat. Sci. 



Phila., 1865, p. 59. 

 1879. Mopalia sinuata Dall, Proc. U. S. Nat. Mus., v. 1, 



p. 303, 306. 

 1886. Placiphorella (Osteochiton) sinuata Dall, Proc. U. S. 



Nat. Mus., v. 9, p. 211. 

 1893. Mopalia sinuata Pilsbry, Man. Conch., (1), v. 14, p. 



303, pi. 62, f. 95-97. 



Recorded range: Pleistocene (?): Deadman Island, San 

 Pedro, California ( !). 



Living (sinuata): Forrester Island, Alaska (!), to San 

 Francisco Bay, California (Newcomb) ; 0-30 fathoms. 



Material Examined : A single anterior valve in the Arnold 

 collection from Deadman Island, San Pedro, California [717], 

 exact horizon unknown. 



Remarks: The single specimen seen is remarkably close to 

 the recent Mopalia sinuata Carpenter, and further material 

 may confirm my surmise that it belongs to this northern 

 species. The fossil agrees with recent shells in its relatively 

 clean-cut, continuous ribs, and the peculiar, deeply pitted reticu- 

 lum which occupies their interspaces, a sculpturing wholly un- 

 like that of any other of the Mopalias thus far described. It 

 is very unfortunate that the exact formation from which the 

 specimen was taken is unknown. 



14. Mopalia, sp. indet. 

 Material Examined: 



