Nick Hawkins / Northern moon snails (Euspira heros) move over a sandy bottom off Nova Scotia, Canada. August

Nick Hawkins / Northern moon snails (Euspira heros) move over a sandy bottom off Nova Scotia, Canada. August

Sue Daly / Egg mass of Necklace shell (Euspira catena) Jersey, British Channel Islands, June 2015

Juergen Freund / Starry moon snail (Natica stellata) Komodo NP, Indonesia.

Philippe Clement / Drill hole in Common / Edible cockle (Cerastoderma / Cardium edule) shell made by Necklace shell (Polinices catenus), Belgium

Scott Leslie / Northern Moon Snail (Polinices heros), St. Margaret's Bay, Nova Scotia, Canada

Scott Leslie / Northern Moon Snail (Polinices heros) crawling on the ocean floor, Nova Scotia, Canada

Adrian Davies / Close up of part of "Necklace" of Necklace shell (Euspira catena) egg case, Cornwall, UK. March.

David Hall / Northern moon snail (Euspira heros) on a rock, Cape Ann, Massachussetts, Atlantic Ocean.

David Hall / Northern moon snail (Euspira heros) on a rock, close up, Cape Ann, Massachussetts, Atlantic Ocean.