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.
In fact, there are only three characteristics shared by all living mollusks: the presence of a mantle (the rear covering of the body) that secretes calcareous (e.g., calcium-containing) structures; the genitals and anus both opening into the mantle cavity; and paired nerve cords.