Fig. I. 



Fig. 2. 



Fig. 3- 



PLATE LIII. 

 Hinge of very young Chaina pellucida Conrad ; from San Pedro, California ; 



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



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



p. 1394. 

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



lucida by W. H. Dall ; c.c, cardinals ; res., resiliary pit ; lig., ligamentary 



groove ; p. 1438. 

 Cytherca Willcoxi Dall ; from the Caloosahatchie marls ; Ion. 102.0 mm. ; 



p. 1276. 

 Dosinia liogona Dall, young shell ; Oak Grove sands ; alt. 4.0 mm. ; p. 1230. 

 Cytherea ccesarina Dall ; Chipola Oligocene ; Ion. 66.0 mm. ; p. 1275. 

 Cyathodonta guadelupensis Dall ; Oligocene of Guadeloupe Island, West Indies ; 



Ion. 39.0 mm. ; p. 1527. 

 Dosinia liogona Dall, young shell, enlarged to show serrate posterior cardinal 



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

 Cyathodonta Spenceri Dall ; Oligocene of Guadeloupe Island, West Indies ; Ion. 



4S.0 mm. ; p. 1527. 

 Venericardia nasuta Dall; Eocene of Alabama; Ion. 41.0 mm.; p. 1425. 

 Carditopsis Bernardi Dall, camera lucida drawing; Pliocene of Costa Rica; 



lat. 2.2 mm. ; p. 1438. 

 Venericardia hadra Dall; Chipola Oligocene; lat. 40.0 mm.; p. 1429. 

 Venericardia himcrta Dall ; uppermost Oligocene of Oak Grove, Florida ; Ion. 



SS.o mm.; p. 1430. 

 Venericardia hadra Dall, dorsal view ; Ion. 40.0 mm. ; p. 1429. 

 Cardita (Carditamera) Prestoni Dall, internal cast; Miocene of Florida; Ion. 



58.0 mm. ; p. 1415. 



1626 



