The aperture is ovate approximately half the shell length (Wu et al. The shell is grayish-green to olive green colored and has irregular thin streaks which are reddish to reddish-brown. Identifying features: Has a large shell which can be up to 32.9 mm long and 20.7 mm wide.

3).ĭistribution: Found in the drainage systems of the Ozark Plateaus (Wu et al. Unlike gilled snails, lunged snails do not have an operculum (Hamrsky).įamily Viviparidae Campeloma crassula (previously known as Campeloma subsolidum)Ĭommon name: Ponderous campeloma or Highland campeloma (Wu et al. Many of these lunged snails go above water to breathe, however, many also stay constantly underwater. Lunged snails, on the other hand, breathe through lung-like structures that are present within the mantle (Missouri Department of Conservation). This structure protects the snail from predators and even prevents it from drying out in case it is out of water for extended periods of time. This structure is attached to the foot, and seals the opening when the snail goes back into the shell (Burch). These gilled snails also have a structure known as an operculum. Here, the gills extract oxygen from the water, allowing the snail to breathe (Missouri Department of Conservation). A long tube-like structure draws water into the mantle, which is the tissue that connects the body to the shell. Gilled snails breathe underwater like a clam.

Both of these types of aquatic snails have several species in Missouri (Wu et al. There are two main types of aquatic snails: those with gills, and those with lungs. In dextral snails, the openings are on the right, whereas in sinistral snails, the openings are on the left (Burch). Other than the mouth, the side at which these orifices are located depends on the coiling of the snail. Due to torsion of the snail’s body, the anus is also positioned towards the front. The mouth is located towards the front of the snail’s body, at the head.

This includes the mouth, anus, mantle cavity (that houses the snail’s gills or lungs), nephridiopore (used to disperse gametes) and male and female reproductive openings (Burch). Snails have several orifices in the head and foot parts of their body. Most snails have the ability to withdraw their head and foot back into their shell if they are threatened by predators, or during unfavourable climatic conditions (Burch). However, some parts of the body, known as the head and the foot can be seen outside of the shell when the snail is active. Majority of the snail’s body, known as the visceral mass, is hidden within the shell. It is also important to note that while externally snails might display bilateral symmetry, their internal organs are typically positioned in an asymmetrical manner (Burch).

The reason why this shell is spiral is because most snails have coiled bodies, so the shell is coiled in order to accomodate the body. For most species, the shell is symmetrical, and twisted into a spiral, however, the specific characteristics of these shells, such as shape and color differ from species to species (Burch). Freshwater snails are characterised as having a soft body, which is protected by a hard outer shell which is composed of calcium carbonate and other proteins.

Snail mouth