PLATE XXTTT. 



MIOCKXE ri'XTKX.S. 



[Unli'ss otherwise stiiteil all figures are a]ijnnxiniiitely natural size.] 



Page. 



Fii!. 1. Prden (Liimpecteri) mlijitelensif: n. s|>. U. S. X. M. ti397 79 



ICxterior of uiiil)onal region Mini iiupei'fect car.-j of left valve; altitmlc of fra.ffiiieiit 

 76 mill. Copied from drawing.' liy Hoc-tor INIcCoiinell. .Miocene, Saiila liu-z Mdiin- 

 tainn, Santa Barbara Comity, Cal. 



Fi(i. 2. Pecieii ( Li/wpeden) entrethnus Conrad var. Ii rntiiuis n. var. V. C. Type 77 



Exterior of right valve; altitutle 70 mm. Santa JIargarita formation (upper Mioeene), 

 Monterey (lounty, Cal. (M. I!.) 



Fig. '2(1. Same specimen as fig. - 77 



Profile of right valve, viewed from rear. (M. P.) 



Fio. H. Pccleii [ Lijropecleti ) rdui/liinn n. >ip. 1 >. A . Type SI 



Exterior of right valve; altitude :(7 mm. Miocene (lower), Ojai Valley, \'entnra 

 County, Cal. (M. P..) 



Fi(i. '.ill. Same specimen as fig. .'! 81 



Exterior of left valve. (M. B. ) 



Fr;. 'Mi. Same specimen as tig. 3 81 



Profile of hoth valves, viewed from tlie rear, showing contrai'tion of ilisk. (M. P.) 



Fi(i. 4. Pectin (Priipeaiiiuaiinii ) stdiifonlnniia n. sp. D. A. Type 91 



Mold of interior of right valve and cast of exterior nf left valve; altitude 7 mm.. • '.',. 

 Miocene, Burke ranch, near Stanford Tiii versify, Santa Clara County, Cal. (M. B.) 



Fig. 5. Peclen (Fueudamusluii)) loinpirdfjixin n. sj). W S. N. M. li;49:!l 89 



Mold of exterior cit contorted left valve; altitmle 14 mm., X .'5. 

 Miocene shale, head of Lompico Creek, Santa Cruz County, Cal. (M. P.) 

 190 



