24 Aeolidia papillosa

24 Aeolidia papillosa

A. papillosa eating Metridium senile. It is immune to the toxic nematocysts in their tentacles and exuded acontia, and it ingests them and stores them in cnidosacs at the tips of its cerata for release when it is attacked.
Slug 110 mm long. Southern Norway. April 2017. © R. Dahl.