PL A TE X L I r. 



PLIOCENK AM) QUATEHNAKY ri-'.CTKNS. 



[Unless oIlRTH'isc stnlrcl all liKiir.'s arr iipiiroximulfly imtural size. The linlit in these liKures comes from the right- 



haii.l si.lr, rhi.toKriLiihs hv Rnl|ih Arnold.) 



I'age. 



Fk;. 1. I'nWii {('lihiiiiiix) hnsliihis Si.wrrliy. K. L. P. 108 



Exteriiir of rinht valvi': altitude r,'.> iiiiii. Kt-cciit, .Mmitfivy Hay, Monterey County, 

 C'al. 

 Fi(i. III. Same s|ieeiiiieii ;is lii;. 1 - 108 



Exterior of left valve. 

 Fig. 2. Pcclen ( Cliliimiis) hastiitiif! Sowi-rliy. F. L. B 108 



Exterior of right valve; altitinle 49 iniii. Same Un-ality as Wjz. 1. 



Fi(i. 2((. Same p]iei'imeii as fit;. 2 — — 108 



Exterior of left valve 

 FiG. a. J'cclen (l'lii</iiirliiiiiiiii]riiTiiliirl.ii<i.>\\i-rhy. ]i. A 125 



Exterior of ri<;lil vtilve; altitude 54 umi.; Sail I'eilro formation (I'leistocene), San 

 Pedro, Los Angeles County, Cal. 

 Fic:. 4. /'('(■/, (I ( I'laijmcU-tiiiiiii I rirniliirix Sowerhy. 1 >. A 125 



Exterior of left valve; altitude 49 mm. Same locality as tig. H. 

 Fig. 5. I'ecti/n {T'lagiorlcnium) ciri-idnrU Sowerby, eiinilateral variety. 1>. A : 125 



Exterior of right valve; .iltitude 53 mm. Same loeality as lig. :i. 

 Fig. 6. Perti-ii {I'lui/iorlniiiiiii) ciri'/i/ffc/.'i Sowerliy, ei|uilateral variety. D. A 125 



Exterior of left valve; tiltitude 5<) mm. Same loeality as tig. .'1 



228 



