The anatomic description of Physa cubensis, based on specimens collected in 5 different sites in Cuba, is presented. The anatomic characteristics of the reproductive system as well as mantle digitations give ground for affirming that this is a unique species with external morphological variations and thus it should be kept under the Physa genre. Besides, dispersion diagrams and regression lines of the length in the width were analyzed in the five sites; the L/A (length/width) variation quotient was compared using a variance analysis. Significant differences were observed in the different sites probably due to the feeding sources of each biotope.