Classes

Gastropoda
There are approximately 40,000 living species of gastropoda. They can live in a terrestrial, marine, and freshwater environment. Most species in this class have a shell although some have an internal shell, or none at all. Some examples of this class are snails, slugs, and nudibranchs.

Bivalvia
Bivavlvia species all have 2 shell valves which is how they got their name. Most of this class consists of marine species, while a few are fresh water. Most of them filter feed plankton and other organic matter out of the water. Some species in this class are mussels, clams, and scallops.

Cephalopoda
This class contains the most intelligent, largest, and fastest swimming invertebrates. They all have tentacles, and swim using a jet propulsion system. Masters of disguise, some are capable of changing their colours to match the environment, and hiding in the smallest of nooks, and crannys. Some also have the abillity to squirt ink at an attacker to temporarily blind it to escape. Some species include the octopus, squid, cuttlefish, and nautilus.

Aplacophora
This class contains worm like molluscs that live mostly in deep marine waters. They all lack any eyes, tentacles, or shells.

Monoplacophora
Little is known about this class of mollusc. there are only 11 different living species that have been found. They live in very deep marine waters, and quite closely resemble a limpet.

Polyplacophora
The species in this class have seven or eight dorsal shell plates used for protection. They are mostly found in the intertidal zone stuck to rocks. An example of this species is the chiton.

Scaphopoda
This class contains molluscs that have a tusk like shell with an opening at both ends. One opening is buried in the sand while the other has many tentacles used for feeding. They are all marine species, and they live mostly in shallow to moderately deep waters.

Caudofoveata
Very little is known about this class of mollusc. They are small and wormlike, living with their head buried in the sand. There are only 70 discovered species.