The jackknife clam is an unusual shape and you’ll be able to identify it right away as the one that is sometimes called the “fingernail” shell.
Long (3-4 inches) and whitish colored, the shell is curved in a fashion resembling someones overgrown fingernail. We used to find them along the eastern shore of Florida.
My reference book says that the green jackknife (Solen viridis) is often found in north Florida and has more of a straight edge on one side, and the other type is called the minor jackknife (Enis minor).
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
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.
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 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.
Broken Crown conch, mussel, clam, tagelus, dosinia, little shark’s eye, and tiny marsh periwinkles (one sits on top of a penny).
If you like to camp in a tent in Florida, we’ve seen some nice spots at campgrounds we visit. Here is a short list of what we’ve found for shaded, tent camping.
The jackknife clam is an unusual shape and you’ll be able to identify it right away as the one that is sometimes called the “fingernail” shell.
