PLATE XYIII. 



Koto. All figures on this plate are drawn natural size. 



When two figures occur side by side, tlie left hand figure represents the ancient 

 form from the Omori Mounds. The right hand figure represents the recent 

 form from the Omori shore. 

 When an outline and a dotted line occur together, the dotted line represents 

 the ancient form. The figures marked by a cross also indicate the ancient 

 form. 



Cyelina Cliinensis Chemnitz. 



Tapes sp. 



Mactra venerformis Deshay. 



Mya arenaria Linne. 



Area inflata Eeeve. 



Dosinia Japonica Lischke. 



Cytherea meretrix Linne. 



Natica Lamarckiana Lucios. 



Eburna Japonica Lischke. 



Eig. 



1. 



Fig. 



2. 



Eig. 



3. 



Fig. 



4. 



Eig. 



5. 



Eig. 



•3. 



Eig. 



7. 



Eig. 



8. 



Fig. 



9. 



