EXPLANATION OF PLATE LXXL 



Sii.iouA ckEtacea Oalili p. 628 



1-2. Lateral and cardinal views "f the type specimen. (After 

 Wliitf^eld.) 



vSiJiA'iiA r.TXF.ni.A'iA Conrad p, 629 



3-4, Lateral \ae\\s of the internal casts of two single valves, a 

 left line and right (.me. 



IW'oJhury clay: Li'iilhinl. (los). 



5. Lateral x'lew (.if a small internal east. 



Mi-relHiiilriUc clay-marl; Lciicla. (163). 



6. Lateral \ie\v nf a large internal cast. 



H'l.indhury clay: iicai' Mataicaii. {103). 



j\r.\CTR.\ l'ENTAKGUI,.\RIS n. S]l p. 63 1 



7-8. Views of two somewhat distorted internal casts of single 

 ^'al^■es. 



ll'cicnlbucy clay: Lorillard, (lOl). 



CvMBor[iOR.\ LixTi;.\ (Conrad ) p. 632 



9-10. \'iews iif the internal casts of two single valves. 



CliffzcooJ clay: Cliffwaml FaUit. iiSs). 

 II. View of the internal cast of a single valve. 



Clilfii'ouij clay: near Malaiaan. [107). 

 12-13. Views of the internal casts of two single valves. 



Rcil Bank Sand: Shrcicshnry Riz-cr, ilio). 



ScriizoDESMA APPRESs.v Gabb p. 634 



14. View of the type nf Vclcda tians-ccrsa \\'hitf. 

 Jl'cnanah sand: near i\[arlborn. 

 15-16. A^iews of a right valve and a left \alve. 



Wciicnali sand: ncai' Marlbura, {130). 

 17-18. Cardinal and lateral views of a comjilete si)ecimen from 

 Kaufman. Te.xas. 



CkII. U. S. Xaf. Miis.. A'(.i. 21. w6. 



19. Lateral \iew of a right valve from Chatfield, Texas. 



C'.i//. l\ S- Xal. Museum. 



20. Lateral \ iew nf the internal cast of a left valve. 



jrcnonali sand: near Craz^■fords Comer, (ij6'). 



21. Lateral view of a right \-al\'e, more l.iniadly truncate behind 



than usual. 



Cliffieood clay: Cliffiecd Piduf. (iOJ). 



CVMDOPIIORA TEI.I.IXOIPES ( AVlutfield ), p. 633 



22. \'iew of the type specimen. 



]Veuonali sand: near Marlboro. 



1026 



