38 



of producing an increased current of water 

 over the branchiae. 

 1U9. Unio multiradiatus Lea. River, rather scarce. 



110. Unio iris Lea. River, rather scarce. 



111. Unio novi-eloraci Lea. River, not common. It 



still remains to be proved whether this species 

 and the preceeding are identical or not. 



112. Unio fabalis Lea. River, not scarce; the female 



average rather smaller than the male. In 

 July 1893, an adult male was found with a 

 byssus thread. 



113. Unio rangianus Lea. River, rather scarce. 



114. Unio triangularis Barnes. River, common. 



115. Unio parvus Barnes. Scarce in the river, 



common in the canal. 



116. Unio circulus Lea. It seems that this and U. lens 



Lea are identical, the latter corresponding 

 with the female. Common in the river. The 

 male is constantly much larger and heavier 

 than the female. 



117. Unio tuberculatus Barnes (verncos us Raf.) 



River and larger Creeks, rather common. 

 The shell of the female is different from that 

 of the male by an expansion of the posterior 

 end. 



118. Unio undulatus Barnes. River, Sugar Creek and 



Canal, common. 



119. Unio pustulosus Lea. River, common, large, 



variable. Some specimens are almost covered 

 all over with warts, others show hardly any. 



120. Unio verrucosus Barnes. Scarce in the river, 



large and heavy. 



121. Unio coccineus Hild. River and Sugar Creek, 



rather common ; variable in shape and size. 

 The larger specimens have some undulations 

 below their middle. The nacre is white, or 

 salmon colored to deep pink. 



122. Unio pyramidatus Lea. River, not common. 



Some specimens with very large and heavy 



