466 



CALIFORNIA ACADEMY OF SCIENCES 



[Proc. 4th Ser. 



Living: Santa Barbara, California, to Magdalena Bay, 

 Lower California ; between tides. 



Material Examined : 



fcs. 



Valve 



Locality 



Collector 



Where Deposited 



Formation 



Period 



Ant. 

 Int. 

 Int.. 

 Post 

 Post 

 Ant. 



Post 



Ant. 



Post 



Ant. 



Int. 



Post. 



Int. 



Post. 



Int.. 



Post. 



Int. . 

 Ant.. 

 Ant.. 



Post. 



Pacific Beach, Cal 



Pacific Beach, Cal 



Pacific Beach, Cal 



Pacific Beach, Cal 



Pacific Beach, Cal 



Long Wharf Canyon, Santa 



Monica, Cal 



Long Wharf Canyon, Santa 



Monica, Cal 



Long Wharf Canyon, Santa 



Monica, Cal 



Long Wharf Canyon, Santa 



Monica, Cal 



Los Cerritoe Hill, Long Beach 



Cal 



Los Cerritos Hill, Long Beach 



Cal 



Los Cerritos Hill, Long Beach, 



Cal 



Coal mine, W. side Pt. Loma, 



Cal 



Coal mine, W. side Pt. Loma, 



Cal 



Coal mine, W. side Pt. Loma, 



Cal 



Coal mine, W. side Pt. Loma, 



Cal 



Spanish Bight, San Diego, Cal. 

 Deadman Id., San Pedro, Cal. 

 ? Deadman Id., San Pedro, 



Cal 



Deadman Id., San Pedro, Cal. 



Mrs. Kate Stephens . 

 Mrs. Kate Stephens . 

 Mrs. Kate Stephens . 

 Mrs. Kate Stephens . 

 Mrs. Kate Stephens . 



F.C.Clark... 

 F. C. Clark. . . 

 F.C.Clark... 

 F. C. Clark. . . 

 T. S.Oldroyd. 

 T.S.Oldroyd. 

 T. S.Oldroyd. 

 C.L. Hubbs.. 

 C. L. Hubbs.. 

 C. L. Hubbs.. 



C. L. Hubbs 



Mrs. Kate Stephens . 

 Arnold Coll 



S. Diego Soc.Nat.Hist 

 S. Diego Soc.Nat.Hist 

 Berry Coll. Cat. 3924 . 

 S. Diego Soc.Nat.Hist 

 S. Diego Soc.Nat.Hist 



Berry Coll. Cat. 3963 



Berry Coll. Cat. 3963 



F. C. Clark Coll 



F.C.Clark Coll. 

 Dept. Geology, 



Stanford Univ. 

 Dept. Geology, 



Stanford Univ . 

 Dept. Geology, 



Stanford Univ . 



OldrovdColl. 

 E. P. Chace.. 



S. Diego Soc.Nat.Hist 



S. Diego Soc.Nat.Hist 



Berry Coll. Cat. 3923 



Berry Coll. Cat. 3923 

 S. Diego Soc.Nat.Hist 

 Berry Coll. Cat. 3973 

 Dept. Geology, 



Stanford Univ .... 

 Berry Coll. Cat. 3934 



501] 



347] 

 502] 

 347] 

 501] 



350] 



493] 



503] 



504] 



660] 



661] 



662] 



499] 



500] 

 348] 



670] 

 346] 



San Diego . 

 San Diego. 

 San Diego. 

 San Diego . 

 San Diego. 



Upper San Pedro . . 



Upper San Pedro . . 



Upper San Pedro. . 



Upper San Pedro . . 



Upper San Pedro . . 



Upper San Pedro. . 



Upper San Pedro . . 



Upper San Pedro. . 



Upper San Pedro. . 



Upper San Pedro. . . 



Upper San Pedro. . 

 Upper San Pedro. . 

 ? 



?"Upper San Pedro' 

 ? 



Pliocene 

 Pliocene 

 Pliocene 

 Pliocene 

 Pliocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



Pleistocene 



? Pleistocene 



Pleistocene 

 Pleistocene 



Remarks: In life this fine species is well distinguished from 

 all its described relatives by the peculiarly bristling dorsal 

 girdle scales, but, with fossils, reliance must be had upon the 

 shell characters, which are more variable and perhaps not al- 

 ways so decisive, especially in light of the fact that many 

 specimens are apt to be badly worn. Well preserved material, 

 however, is usually very characteristic. The species agrees 

 with /. acrior in its large size and strongly concave head valve, 

 features in which both these species differ from /. magdalen- 

 ensis, but it differs from both acrior and magdalcnaisis in the 

 very weak, or in adults usually obsolete, sculpture of the central 

 areas. The radial sculpturing of the terminal areas is also 

 less well developed than in either of the other species. In fact, 

 it is difficult at times to make out its presence at all. The 

 lateral areas are usually rather like a weak copy of those of 



