O. deshayesiana is shorter and "chunky", and has a lower spire.  The
differences between O. deshayesiana and O. vesica are well illustrated here:

http://www.gastropods.com/8/Shell_11818.html

http://www.gastropods.com/9/Shell_9589.html

O. vesica auricularia is like the O. vesica shown here, except with a
broader, more expanded lip.

Paul M.

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