Mesogastropoda

Mesogastropoda was for many years a traditional taxonomic group of snails, an order.

Nonetheless, most of the standard texts and field guides on mollusks date from the time period when this classification was still current, and therefore references to mesogastropods or Mesogastropoda are frequently encountered.

The lower taxa that were traditionally contained in Mesogastropoda are now mostly placed in the superorder Caenogastropoda.

Through torsion of the intestinal mass and a spiral movement of the body, the gill, the kidney and the osphradium (which means sensory receptor, or olfactory organ) have disappeared on the right side.

In the Mesogastropoda, the excretory and the reproductive ducts are separated (in contrast with the most primitive prosobranchs).