Classifying Seashells

seashells
Marine mollusk variety

I am not in love with science.  I call my shells by their common names and pay little attention to the Latin names and don’t really care which “family” they belong to, but I realize that some people might.

So this is my attempt to explain the classification of seashells, beginning with the “Class”.

The variety of sea shells is amazingly huge.  I can’t imagine having to organize shells into groups and since the same types can look very different depending on their colors, size and age, but each type has been assigned a “class”.

The class is fairly simple to figure out since each has it’s obvious differences.

Gastropods : Snail type shells that curl around and are all in one piece (univalves).
Bivalves: Shells that come in two parts, such as a clams and oysters.
Cephalopods: Mollusks without shells (mostly – the nautilus is a cephalopod), such as the squid and octopus.
Tusk Shells or Scaphopods: tusk or tooth looking shells.
Chitons: Flattened and plated, very primitive looking.

Sand dollars, sea urchins and sea cucumbers are Echinoderms and not mollusks or seashells.

Wentletrap Seashells

I’ve written about the wentletrap shell before, but didn’t know much about it. I still am not sure which wentletrap this one is. If you can identify it, I’d love to know.  (Now I know what it see – see below.)

They are carnivorous and eat coral and sea anemones.

I had a reader leave a message asking for more information about this shell. Mainly they are whitish and have a spiral shell like in this picture on Patricia B. Mitchell’s site and at Wikipedia.

Mine is shown in the photo below and is 2 1/2 inches long.

My reference book lists many types of Wentletraps found along the eastern and western seaboard of the United States but they all appear to be fairly small. I thought it might be the “brown banded wentletrap” but that one is found in the northeastern US more often than in the south (where I found mine) and it’s max length is only one inch.

Mitchell’s Wentletrap can be larger – the size of mine, but mine doesn’t’ have the lengthwise ridges and according to this source it is an uncommon shell to find… so I wonder.

UPDATE:  I believe this is the boring turret shellSee an image from the Bailey Matthews museum in Sanibel.

shell

Phylum: Mollusca
Class: Gastropoda

Mitchell’s Wentletrap (Amaea mitchelli)