EXPLANATION OF PLATE XXII. 
All the figures are from direct photographs of natural size except for figures 17-10, 
which are enlarged twice natural size. 
Corbicula sandai Reinhardt. 
Fig. I. — Left valve of a ^'^oung shell from Lake Biwa near vSita, Omi. 
Figs. 2-5. — Left valve of a series of shells from Lake P>ivYa near Sita, Omi showing 
the change in shape and growth. 
Corbicula japonica Prime. 
Figs. 6, 7. — Left valves of 2 shells from Osaka, Central Japan. 
Corbicula leana Prime. 
Fig. 8. — Left valve of a middle-sized shell from Hinga, Kiushu Island. 
Figs. 9, 10. — Left valves of two full-grown shells from Lake Biwa, near Otsu. 
Fig. II. — Right valve of a medium-sized shell from Lake Biwa, near Otsu. 
Corbicula leana var. sadoensis (PilsbrjO- 
Figs. 12-14. — Right valves of 3 shells from Sado Island. 
Corbicula atrata Reinhardt. 
Figs. 15, 16. — Right and left valves of two shells from Yokohama. 
Corbicula straminea Reinhardt. 
Figs. 17, 18. — Left valves of two shells from Japan (without precise locality). 
Corbicula straminea var. awajiensis (Pilsbr}^). 
Fig. 19. — Left valve of a shell from Awaji Island. 
