450 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



1864. Mopalia Kennerleyi var. Swanii Carpenter, id., p. 627, 

 648. 



1864. Mopalia Kennerleyi var. Swannii Carpenter, Ann. Mag. 



Nat. Hist, (3), v. 14, p. 426. 



1865. Mopalia Kennerleyi Carpenter, Proc. Acad. Nat. Sci. 



Phila., 1865, p. 59. 

 1879. Mopalia Wossnessenskii Dall, (pars) Proc. U. S. Nat. 



Mus., v. 1, p. 305. 

 1893. Mopalia ciliata Pilsbry, Man. Conch., (1), v. 14, p. 303. 



pi. 64, f. 64-68. 

 1919. Mopalia ciliata Chace and Chace, Lorquinia, v. 2, p. 42 



[2] (recorded from Pleistocene of Pt. Fermin, 



Cal). 



Diagnosis: Valves moderately heavy, rather distinctly 

 beaked ; lateral areas distinct, bounded by a low, granose rib in 

 front, and with the sutural margin also more or less granose. 

 the area between filled with rows of smaller grains ; head valve 

 similarly sculptured, bearing 8 radial series of low tubercles ; 

 pleural tracts somewhat excavated, sculptured by numerous 

 fine, sinuous, rather granular, weakly interlatticed, longitud- 

 inal riblets, the jugal tract with sharper, finer and closer sculp- 

 ture ; sutural laminae and teeth long and projecting; sinus wide 

 and spongy; tegmental border of median valves sinuous in 

 front, but not false beaked ; tail valve with a single pair of 

 lateral slits and a large, rounded, posterior sinus ; mucro well 

 behind the middle; eaves spongy and crenulated; slits 8, 1-1. 

 1-1. 



Recorded Range: 



Pleistocene: Lower San Pedro Series — Chiton Bed. 

 Point Fermin, California (Chace and Chace, !) ; near light- 

 house, Point Fermin, California (!). 



Formation doubtful — Deadman Island. San Pedro, 

 California ( !). 



Living: Aleutian Islands (Keep), to Todos Santos Bay, 

 Lower California ( !) ; between tides and to 50 fathoms. 



