GILL-BREATHING ("RIGHT-HANDED") SNAILS
[ Order Gastropoda ]
The vast majority of fresh water snails have a spiral shell. Eight genera of snails in the U.S. (Fresh Water Limpets)
have a shell in the shape of a very low cone. Snails like waters with high calcium carbonate concentration (hard water).
That is what they build their shells from. Our waters here in Northeast Ohio are rich in calcium carbonate.
Snails are "right-handed" or "left-handed." You can tell the difference by holding the shell so that its tip is upward
and the opening toward you. If the opening is to the right of the axis of the shell, the snail is termed
dextral -- that is it is right-handed. This types of snails are very sensitive to pollution. They need plenty of oxygen
to survive. If the opening is to the left of the axis of the shell, the snail is termed sinestral -- that is it is
left-handed. These are also known as pouch snails.
Right-handed snails are also known as Prosobranch, or gill-breathing snails. They possess a chalky plate called an
operculum on top of their foot, which they use like a door to close the shell opening. The length or width of the shell
ranges between 2 to 70 mm. The great majority of shells are black, brown, tan and gray in color. The greatest majority of
Gastropods are vegetarians, eating algae, and dead and decaying plants. Most often snails can be found in waters less
than 3 meters deep in more calmer parts of the stream. Several families of gilled snails are Ampulariidae,
Bithyniidae, Viviparidae, Valvatidae, Pleuroceridae, Thiaridae, Hydrobiidae and Neritidae.