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How Is A Seashell Made?

Cypraea chinensis with partially extended mantle.
Image via Wikipedia

A mollusk is the animal living inside a shell.  All mollusks begin as tiny creatures with genetic programming telling it how it will look – basically.  Just like we have characteristics of our parents, the shell begins life looking like it’s ancestors.

As the snail inside grows, the mantle continues to add calcium carbonate and conchiolin to the outer surface of the shell to expand it. Because the mantle is constantly rubbing the surface of the shell it becomes smooth and sometimes very shiny. The shells hardness and colors come from the calcium layers deposited by the mantle. The mantle is also responsible for creating the shape, spines and grooves in the shell.

The mollusks choice of food and habitat also may contribute to it’s coloring. As it grows and moves about feeding and doing what mollusks do, it is all the while creating a beautiful work of art unlike any we could ever duplicate.

Please respect all living mollusks and observe them in their habit, but leave them alone – as I’ve said in a previous post, take your camera to the beach.

Reference: Sanibel Seashells Blog

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The Alphabet Cone Shell

Lamarck - Conus Plate 318
Image by WikiMechanics via Flickr

Cone shells are fairly small shells that are shaped like – can you imagine? – a cone.  Think of a pointed ice cream cone – a sugar cone – without an opening for the ice cream.  Instead you will see a tight, fairly flattened spiral.

They can be found all along the coast of Florida and over to Mexico. Other types of cone shells can be found in tropical waters from the Carolinas to the Indian and western Pacific oceans. The mollusk uses poison to kill it’s prey and in the larger species it can be fatal. Always be careful when handling live cones, although here in the US we don’t have the large ones.

The outside of the Alphabet cone (Conus spurius atlanticus)- scroll down the page at FloridaSheller.com to see his collection – is smooth with reddish brown or orange to yellow spots in irregular shapes.  These shells are not exceptionally large and only grow to about 3 inches (7.6 cm) long, but they have the most interesting patterns on the outside of the shell.  In fact there is a man who has collected the “alphabet” in cones – read about him here.

Little White Moon Snail Seashell

moon snail shell
Milk Moon Snail

There are many types, shapes and sizes of the moon shell family (Naticidae) but this little snail stands out because of it’s milky white and very glossy appearance.

The Milk Moon Snail (Polinices lacteus) is a common find on the beaches from North Carolina to Brazil and will be fairly small. Mine is only 3/4 of an inch (1.9cm) long and less than 1/2 inch (1.3cm) high. They can be as large as 1 1/2 inches (3.8cm) . The Latin “lacteus” means “milk white”.

moon snail shell
Bottom of the Milk Moon

It’s shape is very much like other moon snails and the shark’s eye shell. In New England there is a larger moon shell that can grow up to 5 inches (12.7cm) and feeds on clams. That one is the Common Northern Moon Shell and can be found as far north as New Brunswick and all the way down to North Carolina.