258 Trans. Acad. Sci. of St. Louis. 



Family Endodontidae . 



Pyramidula alternata Say. 

 Common. 



Helicodiscus LINEATU8 Say. 

 Common. 



Family Zonitidae. 



ZoNiTOiDES arboreus Say. 

 Very common. 



Issued May 9, 1905. 



