Whelks
From Cookipedia
A whelk is one of several species of large sea snails, marine gastropod mollusks found in temperate waters.
In North America, the word whelk is used for "busycon whelks", several species of large, usually edible Busycon snails, marine gastropod mollusks in the family Melongenidae.
The edible European and northern Atlantic whelk is Buccinum undatum. There are cooked by boiling in salt water, preferably sea water.