180 



PROCEEDINGS OF THE ACADEMY OF 



[May, 



Baker (1910) found in Lymncea rejiexa that the length-breadth ratio 

 of the shell increased with the length of the shell. That is, the 

 larger shell had the higher ratio and therefore a higher spire. Tables 

 I and II show this relationship in Lymncea columella from about 

 Philadelphia and on both tables the length in millimeters is the 



