Mollusca (Invertebrates)

Gastropoda
Gastir means stomach and podi means ‘foot’. Because of this, gastropods can also be called ‘stomach-footed’. This class contains single-shelled cowries such as slugs and snails.

Bivalvia
The organisms in this class don't have tentacles.They include clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater.

Aplacophora
These deep marine water mollusks don't have shells. This class contains 28 families and 320 species. The foot and mantle cavity are reduced. There is no head and there is no specialized excretory organ.

Monoplacophora
The name means with one plate (one shell). Head is reduced to no tentacles or eyes; they have a rounded foot. Many of the gills are paired.

Polyplacophora
Polyplacophora means having may plates. There are eight plates present. The eyes and tentacles are absent. An example of polyplacophora are chitons.

Scaphopoda
Shells of this species range from about 0.5 to 15 cm in length.The mantle of a scaphopod is entirely within the shell.

Cephalopods
These organisms have tentacles or a pair of arms.This class class includes octopuses, squid, and cuttlefish. Cephalopods are found in all the oceans of Earth.