EXPLANATION OF PLATE XXVII. 
Figure 1. SpH#RIUM STAMINEUM Conrad. _ 
‘2. SPH&RIUM STRIATINUM Lamarck. 
‘« 3. SPHARIUM SIMILE Say. 
‘ 4, SpH#RIUM SOLIDULUM Prime. 
‘5. CALYCULINA TRANSVERSA Say. 
‘« 6. CALYCULINA PARTUMEIA Say. 
‘© 7%... SPH@RIUM FABALE Prime. 
‘t 8. CALYCULINA TRUNCATUM Sinsley. 
‘¢ 9. CALYCULINA SECURIS Prime. 
‘* 10. SPH#RIUM OCCIDENTALE Prime. 
‘* 11. ALAasMODONTA COMPLANATA Barnes. Juvenile. 
‘* 12. ANODONTA GRANDIS Say. Juvenile. « 
‘* 13. QuaDRULA PUSTULOSA Lea. Juvenile. 
Natural diameter. 
