Transform Boundaries The final type of boundary is one where the two plates slide against each other in a sideways motion. These boundaries between plates is referred to as transform boundaries.
The three regions of the body of the Mollusk are the head-foot, the visceral mass, and the mantle-shell.
Body Plan. Mollusks have a thin layer of tissue called the mantle. The mantle covers the body organs, which are located in the visceral mass. Between the soft body and the mantle is a space called the mantle cavity. Mollusks contain gills.