[89 Costa Rica Miocene — Olsson 17 



with that characterizing the Chesapeake Miocene fauna of the 

 eastern United States and shows their close agreement in age. 

 The recent species and their closely related forms in the Gatun 

 fauna are as follows: 



Area occidentalis Phil. West Indian 

 Area unibonata Lamarck West Indian 

 Area Candida Gmelin West Indian 

 Area auriculata Lamarck West Indian 

 Ostrea megodon Hanley Pacific 

 Anoinia simplex d'Orb. West Indian 

 Phacoides radians Conrad var. niedioamerieanus 



Olsson West Indian 



Phacoides trisulcaius Conrad West Indian 



Glycymeris castaneus Lamarck West Indian 



Glyeymeris deeussatus Linne West Indian 



Divaricella quadrisulcaia d'Orb. West Indian 



Cardium medium Linne West Indian 



Cardium spinosiim var. Turtoni Dall East Atlantic 



Carditim- serratutn Linne West Indian 



Pitaria circinata Born and its var. alternata Broderip 



West Indian and Pacific 



Antigona jnuliicostata Sowerby Pacific 

 Antigona rugosa Gmelin West Indian and Pacific 

 Maeroeallista maeulata Linne West Indian 

 Chione grzis Holmes West Indian 



Tellina crystallina Chem. West Indian and Pacific 



Strigilla pisiformis Liune West Indian 



Mactra exoleta Gray Pacific 



Mactra alata Spengler West Indian 



Labiosa li^ieata Say West Indian 



Corbula Dietziana C. B. Adams West Indian 



Tellidora cristata Recluz West Indian 



Conus proteics Hwass West Indian 



Co?ius floridanus Gabb var. costarieensis Olsson West Indian 



Terebra betithalis Dall var. bocase^isis Olsson West Indian 



