Cephalic Tentacles: sensitive projections often used for sensing water vibrations and feeling surrounding objects.

Radula: transverse rows of small chitinous teeth, part of the anteriorly positioned mouth.

Foot: Fleshy, muscular structure used for locomotion, plus hunting and reproduction in some taxa. (More information of muscular foot under Appearance).

Gill: counter current respiratory structure that may be bipectinate or monopectinate in gastropods. Mesogastropoda are Monopectinate representatives.

Visceral Nerve Cord: Nerve cord running posteriorly from the cerebral ganglion to the visceral ganglia (Rawat, 2010).

Pedal nerve cord: Nerve cords running ventrally from the cerebral ganglion to another ganglion in the foot (Rawat, 2010).

Cerebral Ganglion: concentrations of nerve tissue situated above the digestive tract. Gives rise to nerves that provide the head region and associated sense organs. May connect additional ganglion to form central nervous system (circumenteric nerve ring).

Stomach: weakly muscularized region of the digestive tract between the oesophagus and intestine. Important location of food digestion.

Digestive gland: sometimes referred to as the midgut gland, this structure specialises in the creation of digestive fluids.

Gonad: may be the ovaries or testies depending on if it is male or female specimen.

Nephridium: Release metabolic waste products from the blood into the mantle cavity, waste removed by the current flowing out of the shell once past the gills.   

Pericardium: a thin walled, ovoid chamber that encircles the heart.

Auricle: Part of an open circulatory system, collects oxygen rich blood from the gills.

Ventricle: Pumps blood from the auricle into small vesicles, carrying the oxygen enriched blood to the organism’s tissues.

Note: Above information from Ruppert, et al. (2004).