Polyplacophora Class ("many plates"): The dorsal surface of these mollusks has a limestone reinforcement composed of partially overlapping plates. One representative is the chiton. They are all marine.
Scaphopoda Class ("canoe-shaped foot"): Small animals with an elongated conical shell. They are marine, and live partially buried in the sand. Known in general by teeth.
Dentalium (dentium or elephant tooth)
Gastropoda Class ("stomach in feet"): corresponds to the largest group of mollusks, marine, freshwater and terrestrial environments. These are the well-known snails, snails and slugs. The shell, when present, has a helical shape.
Bivalvia class (two shell halves): They are also found in fresh or salt water. Its shell has two parts that completely enclose the animal's body. The most familiar examples are oysters, mussels and clams. They present the gills covered by a mucus layer; As it passes through the gills, food particles adhere to the mucus and are carried into the mouth.
Bivalos are responsible for producing pearls of commercial value, although any shelled mollusk can make them. The pearls are formed by the deposition of nacre around a strange particle that penetrates between the mantle and the shell.
Cephalopoda class ("head to toe"): molluscs without an outer shell, which have a very different internal structure and morphology from the others. They are octopus, squid, nautilus and squid, exclusively marine animals. The cephalopods' feet are divided into tentacles.
Beached giant squids on the beach
In the squid, there are 10 tentacles and two of them are more developed than the others.. In the octopus, the tentacles are eight and all the same. In each tentacle there are suction cups that adhere to the substrate, which favors the octopus locomotion on rocks. The suction cups are also useful in grasping food that is then carried to the mouth by the tentacles.
Ink Bag: Protection
Among the organs that make up the viceral mass, the squid has an ink bag. This is compressed every time the animal feels threatened by an enemy, which causes the release of ink that comes out in jets by the siphon. The stain that the ink leaves on the water confuses the predator while the squid escapes quickly.