PLATE LIII. 

 Fig. I. Hinge of very young Chama pellucida Conrad; from San Pedro, California; 



the valve 2.0 mm. long, much magnified, drawn with camera lucida by 



W. H. Ball ; card., cardinal teeth ; lot., lateral laminae ; lig., ligament ; 



P- 1394- 

 Fig. 2. Hinge of Erycinella ovalis Conrad, much enlarged and drawn with camera 



lucida by W. H. Ball ; ex., cardinals ; res., resiliary pit ; lig., ligamentary 



groove; p. 1438. 

 Fig. 3. Cytherea Willcoxi Ball ; from the Caloosahatchie marls ; Ion. 102.0 mm. ; 



p. 1276. 



Fig. 4. Dosinia liogona Ball, young shell ; Oak Grove sands ; alt. 4.0 mm. ; p. 1230. 

 Fig. 5. Cytherea casarina Ball ; Chipola Oligocene ; Ion. 66.0 mm. ; p. 1275. 

 Fig. 6. Cyathodonta guadelupensis Ball ; Oligocene of Guadeloupe Island, West Indies ; 



Ion. 39.0 mm. ; p. 1527. 

 Fig. 7. Dosinia liogona Ball, young shell, enlarged to show serrate posterior cardinal 



tooth ; Ion. 4.0 mm. ; p. 1230. 

 Fig. 8. Cyathodonta Spenceri Ball; Oligocene of Guadeloupe Island, West Indies; Ion. 



45.0 mm. ; p. 1527. 



Fig. 9. Venericardia nasuta Ball ; Eocene of Alabama; Ion. 41.0 mm. ; p. 1425. 

 Fig. 10. Carditopsis Bernardi Ball, camera lucida drawing ; Pliocene of Costa Rica ; 



lat. 2.2 mm. ; p. 1438. 



Fig. ii. Venericardia hadra Ball; Chipola Oligocene; lat. 40.0 mm.; p. 1429. ^ 

 Fig. 12. Venericardia himerta Ball ; uppermost Oligocene of Oak Grove, Florida ; Ion. 



55.0 mm.; p. 1430. 



Fig. 13. Venericardia hadra Ball, dorsal view ; Ion. 40.0 mm. ; p. 1429. 

 Fig. 14. Cardita (Carditamera) Prestoni Ball, internal cast; Miocene of Florida; Ion. 



58.0 mm.; p. 1415. 



1626 



