The Common Egg Cockle
Laevicardium serratum (Linnaeus, 1758)
Family Cardiidae
The Common Egg Cockle has a smooth, egg shell-like shell which grows up to 3". The scientific name, Laevicardium serratum, alludes to the finely serrated internal surface of the shell edges [Mitchell]. It's fairly common on S. Hutchinson Island beaches but is often cracked or damaged as it does not have a thick shell. I have 50-60 versions in my collection some have coloration and slight patterns.