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.
Mollusks usually have a shell (although some do not). Mollusks also have an extension of the body wall called the mantle. This portion of the animal's anatomy is responsible for secreting the shell. The mantle encloses the mantle cavity which contains the Ctenidia (gills), anus and excretory pores. Many mollusks have a radula, a tongue of sorts, which is rough like sandpaper and is used to rasp away at food. The radula is made of a hard material called chitin, the same material of which Arthropod exoskeletons are made.