[The emigration of Gastropods from the sea : II. Studies on Limatpontia capitata, L. depressa und Assiminea grayana]

Abstract

The higher marine Gastropods live on the shore the more their salinity tolerance increases. This is expressed in the animals' survival, their growth rate, and their reproduction rate on extreme salinity concentrations. In all the three gastropod groups-Opisthobranchia (Limapontia depressa), Prosobranchia (Assiminea grayana), Pulmonata (Ovatella myosotis)-a more or less effective hyperosmotic regulation has evolved which enables the animals to live with low salinity concentrations in their surrounding. In high salinities they are poikilosmotic. Adult supralittoral Gastopods can stand considerable salinity changes. The eggs are more delicate: The embryos develop best when the eggs stay on the salinity where they were produced even if the concentrations are extremely high or low.