Collecting Seashells: Types of Shells

All the shells you see dotting the beach were made by the creature who lives (or lived) inside.  The mollusk is a marine snail and it's life becomes a work of art in the form of it's shell. 

Mollusks can create a shell that is either all in one piece, or in two sections that are hinged together.  The snails that create one, coiled shell are called gastropods, or sometimes "univalves", while the bivalves are the ones with two separate shell parts, like clam shells.

Generally, the difference in the shells depends upon  the lifestyle of each.  Gastropods crawl along the ocean bottom or among coral using a strong "foot" in search of food, while the bivalves attach themselves to something and are stationary, grabbing food as it flows past. (Photo: crown conch)

All seashell photography on this page is my own, unless otherwise stated.  My pictures are NOT free for use by others for any reason.

These are the cowry, or sometimes spelled cowrie, shells. I purchased them and didn't find them on the beach. Both are quite large, with the Atlantic Deer cowry (on the left in the photo) is about four inches long.

This type of shell is coveted by collectors for it's shiny porcelain appearance.  I remember when I bought it that I wondered if it was a real shell because it seemed like it was made of glass.

Some of the cowry shells were used as currency all over the world, many years ago. They are called money cowry - appropriately enough.  In fact, I have read that in some places the shell is still used as such.

Smaller versions of this shell are often used to make jewelry, and often times people will own a cowry necklace.

Florida has many miles of beaches, but for the serious shell collector, the Gulf coastline is the best  place to do some beachcombing.

The beaches of Sanibel Island are known as one of the best places in the world for shell collecting - coming in at #3 - for it's shell abundance and variety.  It's the place where you could find a Junonia (pictured) which would be a treat.

Florida gastropods (single shell) you may find on both sides of the state include the following:

• Slippersnail or Slipper shells (1-2 inches)
• Shark's Eye (max 3 inches)
• Fighting Conch (max 4 inches)
• Worm Snail (length varies)
• Cerith (about 1 inch)
• Scotch Bonnet (max 4 inches)
• Nutmeg (less than 2 inches)
• Tulips (can be 4-5 inches)
• Whelk shells (Lightning - see below, Pear and Knobbed)
• Lettered Olive shells 

I've had these two shells (above) for years but I only knew that the large one was a lightning whelk. The identity of the small one eluded me.

As I was going through my seashell collection one day, I looked more closely at the little one and it dawned on me!  It was a juvenile  lightning whelk!  I guess an expert would have known right away, but besides the fact that it is shaped the same, and the coloring of dark lines over white is similar, it's opening is on the left side!

Lightning whelks are sinistral, meaning that when you hold them by the tip, or bottom, the aperture will be on the left as opposed to the right like most seashells.  I'm glad it is now identified!

My photo here shows the whelk (right) with the strawberry conch.

Bivalve shells are simply shells that were formed in two parts, such as the clam, scallop and oyster.

Usually you will find one part of the shell washed up on the beach as it has broken apart while being rolled in the surf. Finding a whole set, that is not alive, is a great find in my opinion.

On the east coast of Florida the cockle shell (pictured here) is widely found and it can be white, tan, gray, brown or any combination it seems.

Also common finds along the east coast are the large pen shells, tiny coquinas, and numerous other types of clams and cockles.

The colors of shells are determined by their species and heredity mostly, but also by what the mollusk (animal inside) eats.

They have a fleshy mantle, or "cape", that may either partially, or totally, cover the outside of the shell and it secretes a calcium solution which grows the shell larger while creating the colorful patterns and ridges.  (The Flamingo Tongue shell is totally covered by a pretty, spotted mantle which is not part of it's shell.)

The mantle also polishes the part of the shell it touches and that is why some shells are very shiny. The coloring can also add hardness and be a camouflage to predators.  A good example of the use of shell camouflage, called countershading, is the Chambered Nautilus (see below).

The shape and type of shell produced will have to do with how and where the animal lives and hunts for food. If the shell has spines, like the murex, it may be to discourage predators, and if it's long and coiled, like the olive shell, it is useful for burrowing through sand.

Sealife is amazing and diverse.

Ask anyone what they would love to find while visiting the ocean and they will probably say a starfish or a sand dollar.

Sea stars (commonly called starfish) and sand dollars are not really shells.  They are echinoderms and if you find a dead one, you are seeing the exoskeleton of the once living animal. 

Sand dollars live on the sandy ocean floor and sea stars are also ocean dwelling, either moving over the bottom or clinging to coral and sea fans.  

They don't come up on dry land unless they have been washed up on shore by a storm, and then (if they are alive) they won't be white.  Sand dollars are generally dark colored and can be covered with fuzzy hairs in some cases.  Living ones will not look like the one in this photo.  If you find a white sand dollar on the beach, it has died and been bleached white by the sun.

The sea urchin also belongs to this group, and all of these treasures will be more fragile than seashells and will break easily, so be more careful when collecting them.

Everyone who strolls the beaches would love to find that one beautiful, large shell.  Just imagine catching a glimpse of the protruding spire, with the rest buried in the soft sand, as the surf rushes out.  You run to the spot before it's covered with the incoming waves and quickly dig it up.  Wow, what a specimen!

I suppose it does happen, but in all my years of visiting east coast Florida beaches, I have never had this experience. Many mollusks who build these homes (shells) live in deep water and some are now protected species.

In fact the beautiful Queen conch's (pictured) numbers are in decline from over-harvesting for souvenir shops and food.  Conch meat is served in local restaurants on the Florida Keys and elsewhere.  And although this shell has been protected since 1985, it is making a slow comeback - read more at Jaxshells.org's "Who Counts the Conchs?"  Finding large shells usually means they are inhabited, so be sure to put them back after you take a photo to remember your find.

Seashells will be empty if they are "dead" and okay to collect.  If there is something protruding from the opening, or you see a hard cover over the opening, that means it is still occupied.

Take a photo and leave the little guy where you found him!

Every shell is unique and beautiful in it's own way and if you can get past the "bigger (shell) is better" mentality, you will discover some wonderful shells right under your feet.  In Florida the coquina clams are abundant and can make a colorful collection.  Conquinas can be just about any color and they live right along the wave line.  In fact when you see shore birds feeding in that area, they are probably eating coquinas.  Since they are so abundant, finding empty coquina shells are easy.  In fact I don't have many in my collection because they were so common to see on the Florida coast, I just did not collect them.

Other commonly found (in certain areas) small bivalves include jingle shells, kitten's paw, oyster and scallop shells.  (The purple and pink splotched shells in this photo are calico scallops).

LIttle gastropods (coiled shells in one piece) can be a great find with bumps and swirls of color, such as the Common nutmeg, moon snail and cowrie.  And remember that the large shells will begin as juveniles and sometimes tiny versions of a magnificent shell can be found.

Small empty (dead) seashells can be collected and used for crafts or decorating so don't overlook the little shells.

(Photo of tropical shells by P. Carter)

A tropical beach vacation is something many people plan all winter long so don't let your lack of knowledge get you into trouble. 

In many areas taking live seashells from their habitat is illegal.  Also disturbing dunes and especially turtle nests can get you into trouble.  Be aware of the rules and laws wherever you visit or vacation and don't disturb or collect wildlife.

If you do take living sand dollars or seashells, you will be sorry when the animal dies and begins to stink.

Also be aware that hurricane season in Florida runs from June 1st through November 31st with August and September being the two most active months.  You can't help it if a hurricane forms while you are on vacation, but knowing about evacuation proceedures and what to expect ahead of time is a good idea.

(Photo: Sea turtle nest marker.  Credit:Morguefile)