EXPLANATION OF PLATE LIX. 



VeniELLa tkiguna ( Gabb) P- 537 



1. Lateral view of an internal cast of tbe left valve. 



Navcsiiik- marl: near U'aliiford, {147'). 



2. Lateral view of an internal cast of tlie left valxe. 



3. Lateral ^'icw of a plaster cast taken from the natural mould 



of the exterior of the same specimen of which fiff. 2 is 

 the internal cast. 



rinton Pn'ds; Bd-rs Hill Cut, (i2cf). 



Ete.a carolinensis Conrad p. 54i 



4-5. E-xternal \icws eif a right and a left valve. 



6. Internal \-icw of a right \-al\e. showing the hinge. 



MarslinlllirK'ii clay-marl ; near Su'cdrsboro, (177). 



Etea trapezothea ( Conrad ) p, 543 



7. Lateral \'iew of a somewhat distorted interna] cast of a riglit 



valve, 



Mci-fhanlz-illc clay-inai-l ; I.cnola, (l6s). 



Ete.a delaw.\rensis ( Galjli) p. 546 



8-9. Cardinal and later.al views of a nearly perfect internal cast. 

 Maiia.uiiiaii marl; Pcinbcrton, (loi). 



1000 



