The pouch snail may be found in streams that are fairly clean. However, their dominance may indicate that dissolved
oxygen levels are low. These snails are different from right-handed snails because they do not breath
under water by use of gills but instead have a lung-tike sac called a pulmonary cavity which they fill with air at the
surface of the water. When the snail takes in air from the surface, it makes a clicking sound. The air taken in can
enable the snail to breath under water for long periods of time, sometimes hours.
The pouch snails have two characteristics that will help you identify it. First, it has no operculum, or hard cover
over the opening to its body cavity. Second, snails are either "right-handed" or "left-handed," and the pouch snails
are "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 left of the axis of the shell, the snail is termed sinestral -- that is it is left-handed. If the opening is to the right of the axis of the shell, the snail is termed dextral -- that is it is right-handed, and it breathes with gills.
Snails are animals of the substrate and are often found creeping along on all types of submerged surfaces in waters
from 10 cm to 2 m deep. Common pulmonate snail families are Physiidae, Lymnaeidae, Planorbidae, Ancylidae, Lancidae and