1.1. Chitons have a dorsal shell which is composed of eight separate shell plates or valves. These plates overlap somewhat at the front and back edges, and yet articulate well with one another.
1.2. They eat algae, bryozoans, diatoms, and sometimes bacteria by scraping the rocky substrate with their well-developed radulae.
1.3. They live on hard surfaces, such as on or under rocks, or in rock crevices. Some species live quite high in the intertidal zone and are exposed to the air and light for long periods.
2. Cephalopoda
2.1. head is surrounded by a foot divided into tentacles
2.2. They feed by capturing prey with their tentacles, drawing it into their mouth and taking bites from it.
2.3. Octopuses swim headfirst, with arms trailing behind
3. Bivalvia
3.1. bodies enclosed by a shell in two hinged parts The shell of a bivalve is composed of calcium carbonate, and consists of two, usually similar, parts called valves.
3.2. Most bivalves are filter feeders, using their gills to capture particulate food such as phytoplankton from the water
3.3. Most bivalves bury themselves in sediment on the seabed, where they are safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. A few bore into wood, clay or stone and live inside these substances. Some bivalves, such as the scallops, can swim.
4. Gastropoda
4.1. Most shelled gastropods have a one piece shell, typically coiled or spiraled. This coiled shell usually opens on the right-hand sid
4.2. Marine gastropods include some that are herbivores, detritus feeders, predatory carnivores, scavengers, parasites, and also a few ciliary feeders, in which the radula is reduced or absent
4.3. they move by sliding on their stomach which doubles as the foot
