Egg cases - shoreline Conwy (1 of 1)

Egg cases - shoreline Conwy (1 of 1)

Observation - Egg cases - shoreline Conwy (1 of 1) - UK and Ireland. Description: I don't know what this is other than egg cases of a marine animal. The longest part of this group of cases measures about 3 inches. Anyone any idea?

I don't know what this is other than egg cases of a marine animal. The longest part of this group of cases measures about 3 inches. Anyone any idea?