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.
For most mollusk, their shell is external including snails, scallops, oysters, clams and mussels. For other mollusk, like squid, and cuttlefish, they have a internal skeleton similarly to a shell. There are also some that do not have a shell at all, like octopus and slugs, with only a mantle for protection of organs. SYMMETRY. Mollusks have bilaterally symmetry, meaning that they have a body arrangement that is symmetrical, along the center. Also, when the body is divided into two, they are alike.