KING HELMET SHELLS (Cassis tuberosa) FROM THE DELPHI COLLECTION
It’s time to look at another shell from Delphi. The club has glass jars displaying small shells in the Great Room. Larger shells like the ones below are displayed on shelves. The King Helmet is the largest of the helmet shells of the family Cassidae. They are found in the Western Atlantic from North Carolina through the Caribbean and the gulf of Mexico down to Brazil. They tend to bury themselves during the day, becoming active and feeding at night. In humans this behaviour is found mainly in students and in those involved in the music business and similar louche occupations.
King Helmets prey mainly on sea urchins and other echinoderms, using their foot to grip their meal. The dining arrangements are somewhat protracted. The snail makes a hole in the urchin through the combined action of a glandular secretion which is rich in sulphuric acid, while using itsRADULAto rasp and dig through the shell to get at the trapped occupant, which it gradually consumes… That’s enough about that.
We recently discovered this shell loitering at the back of a drawer. It may well have been there for a couple of years… I had no idea what species of gastropod it might be, so I turned to a book I recently bought (and am about to review), the Peterson Field Guide on Shells. It is extremely thorough and well-illustrated, and almost at once I was able to pick the shell out as a STOCKY CERITH Cerithium Litteratum (Colin – are you still keeping an eye on the shell ID errors in this blog, I wonder? Later: yes… and he confirms the ID. Many thanks). It’s a couple of inches long and has 7 spirals before the tip part, with pronounced nobbles on the lowest 4. There’s a neat hole in it, but I don’t know whether caused by sea / beach damage or a predator. These creatures live in shallow water and are common throughout the Caribbean. So this one is nothing unusual, but I am pleased that it has eventually turned up…