Hydatina physis is quite variable in its colour shading. It can range from a
very dark form to a pale pinkish white in which the bluish border is almost invisible.
It has thin brown lines running across the translucent white shell. Hydatina physis
feeds exclusively on cirratulinid polychaete worms.
More informations on Hydatina physis are at
Bill Rudman's Sea Slug Forum!
