P T. A T E X L T A^ . 



ri.KH'ENP: AND (-^rATHKNAKY I'KCTENS. 



[Unless (itlierwisf stated jill limires are appnixiTiiately iiatiirai size.] 



Page. 



Fii;. 1. I'ectri, [Chlauiiix] jiiriliiii! .\rnoh\. U. S. N. M. 162522. Tyi)e 114 



K.xteriiir nl right v;ilvi'; altitiiile 45 mm. Plii)ceni,\ De:ulman Islanil, near San Peilrn, 

 Las Ang(4e.s County, Cal. (Mt-m. (.'al. Acad. 8ci., vol. :!, pi. 12, tig. 6.) (M. P.) 



I'"ii;. l'(. Same specimen ais fig. 1 _ 114 



Kxterior of left valve. (Jiln,,.. pi. 12, fig. 7.) (M. P.) 



I'li;. l/<. Same specimen as lig. 1 114 



Profile nf both valves as viewed fimn tlie rear. (M. P.) 



l"'i(i. 2. I'erteii {('lil(i)iiiif:) liiifitiitiist Sovverby var. .v/cii/cj/ii.v Dall. I). A 113 



Kxterior of left valve; altitude .'!6 mm. I'leistoceiie, near bath liouse, Santa Parbara. 

 Cal. 



I'lc. 2(1. Same s])ecinien as fig. 2 11. '1 



Profile of left \alve as vii'wed from the rear. (M. P. I 



Kici. :;. I'.rhn iCIihiiiniK) hnsliiliis i^.)\\fr\>y \nr. shalnjiis Dall. D. A 113 



Ivxfi-rior of small left valve; altitude 21 mm. Pleistocene, San Pedro formation, Dead- 

 man Island, near San Peilro, Los Angeles Connty, Cal. IM. B. ) 



Fill. 4. Pi'clcii (('lilmnjin) hddatns Sowerby var. titriiteriuis Dall. D. A 11:-! 



Kxterior of right valve showing secondary si'ul[itnre; altitude 21 mm., X 3- Same 

 locality as fig. 'A. 



Fi(i. 5. I'ectcii ( I'ldffiorteniiuii ) cerroseiini.i Gabb. U. S. N. M. til 24(i 123 



Copied from Doctor McConnell's drawing of the left valve of Dall's type of I'ntni 

 nuhvcnirico-ms; longitnde 63 mm. (Trans. Wagner Free Inst. Sci., \ol. :!, ]]t. 4, jil. 29, 

 fig. S. ) Pliocene or Pleistocene, Ventura County, Cal. 



l'i(i. 6. Pi'cli'ii ! I'liu/iort.fiiiuin ) circuhirit! Sowerby. F. L. H 125 



Exterior of right valve; altitude 45 mm. Recent, (Jiilf of California. (!\I. P.) I Pho- 

 tograi)hed without coating by the Williams process.) 



Fiii. (io. Same specimen as fig. 6 125 



Exterior of left valve. (M. B. ) (Xo coating.) 



Flo. 6';. Same sjiecimen as fig. 6 125 



Profile of both valves as viewed from the rear, showing great convexity of the tyj)ical 

 form of tliis sjiecies. (M. P. ) 



Fki. 7. Peclen (I'ldf/iocli'iiiinn) {■!rrn/arl.i Sowerby. IT. S. X. M. 61246 125 



Copied from Doctor ;\[c( 'omiell's drawing of the type (right valve) of Dall's I'n-tcn 

 coinpactan; longitnde 26 mm., X 7/5. (Trans. Wagner Free Dist. Sci., vol. .'!, pt. 4, jil. 

 34, fig. 5.) PU'istocene or Pliocene, Ventura County, Cal. 



Fiii. S. Pi'c/eii ( J'rojiiaiiiumum ) rirersi n. sp. D. A. Ty])e 126 



Interior of riglit valve, showing short internal line; altitmU' 17 mm. I'liocene, Santa 

 Monica Canyon, Los Angeles County, Cal. (S. ) 



Fk;. it. Pci-lfii ( I'nipediimsriun) rir/'mi n. sp. D. A. Cotyjie 126 



Kxterior of iiupi'rfect left valve; longitude 15 mm. Same locality as fig. 8. (S.) 



232 



