Body Plan

The body plans for all terrestrial snails are generally the same. They consist of a shell, the foot, mantle, visceral mass, circulatory system, digestive system, reproductive system, radula, sensory organs, and a nervous system.

This is a pucture of the general layout of a snail compliments of











Shell: Made of calcium-carbonate and used to protect the internal organs (Hickman et al., 2011).

Foot: A ventral muscle used for locomotion.

Mantle: A sheath of skin lining the shell that secretes the shell (Hickman et al., 2011).

Visceral Mass: All the internal organs and external gill, if present (Hickman et al., 2011). 

Circulatory System: Most mollusks have an open circulatory system which means that the blood doesn’t stay within vessels and the heart (Hickman et al., 2011). It travels throughout the body going through channels and sinuses in the tissues, called the hemocoel, after being pumped out by the heart (Hickman et al., 2011). They also have a lung in the mantle cavity and breathe with their pneumostome (Hickman et al., 2011).

Digestive System: The digestive system has similarities to humans in that they have intestines, a stomach, a kidney, a liver, and an anus (Hickman et al., 2011). However, their anus can sometimes end up above their mouths via torsion (Hickman et al., 2011). Torsion is the twisting of the visceral mass that occurs during development (Hickman et al., 2011).

Reproductive System: Snails are monoecious and so they have both male and female reproductive part, but have a spermatophore which holds the sperm cells and the egg cells until reproduction (Hickman et al., 2011).This is a pucture of how the radula works compliments of

Radula: This is part of the mouth used for scraping or tearing anything from flesh of organisms to the algae off of surfaces (Hickman et al., 2011).

Sensory Organs: The sensory organs on mollusks or well developed (Hickman et al., 2011). Snails have two pairs of tentacles, one having eyes on the end with photosensory cells and the other uses chemosensory cells (Hickman et al., 2011).

Nervous System: Snail nervous systems are well developed as they have a cerebral ganglion and nerve cells (Hickman et al., 2011).