CONTENTS 



Plate XV. Unio rectus. 

 ,. XVI. Unio crassus. 



TVTT £ Fig. 1, Unio viridis. 

 " -*-*"■$ „ 2, Unio ochraceus. 



"5TVTTT 5 Fig- 1> Unio nasutus. 

 „ jl v in. ^ ^ ^ Unio j cter i nus# 



XIX. Unio cariosus. 



