Seashell Identification – Common Atlantic Shells

Ribbed mussel shell

Some common long shells found on the beaches I frequent are the pen shell, jackknife clam and stout tagelus.

Pen shells often have an iridescent shine and the ones I find are usually just pieces. An unbroken shell can be close to a foot in length.

According to my Seashell Book, there are three types of pen shell: the sawtooth, stiff and half-naked. Pretty weird names. Contrary to what you might think, the sawtooth is the smoothest looking. The other two have vertical ridges going the length of the top “fan” part of the shell.

pen shells
Pen Shells

The Minor Jackknife Clam Shell

This long, whitish shell is the Minor Jackknife clam. My kids used to call it a fingernail shell. It is also a razor clam.

pen shells and jackknife clam shell
Jackknife clam and pen shells

The longish and wider shells shown below next to my eye glasses are stout tagelus. These are also known as “short razor” clams.

stout tagelus clam shell
Stout tagelus clam shells

Pen shells are related to mussels which are not the prettiest of shells. I have one in my photo below along with a tagelus.

Florida seashells
Broken Crown conch, mussel, clam, tagelus, dosinia, little shark’s eye, and tiny marsh periwinkles (one sits on top of a penny).
Ribbed mussel shell
Open and empty mussel shell

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