Cuttlefish have a bulky body, fins, and 10 appendages. 8 are short appendages called arms and the other 2 are larger and known as tentacles. They have small internal shells like nautiloids but the shell of a cuttlefish is embedded in its mantle.
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Squid have large cylindrical bodies with a pair of fins derived from mantle tissue. Squid also possess 10 appendages called arms that are arranged in pairs of 5 around the head. One pair that is larger than the rest, is called tentacles. Each arm is covered with suckers that are also surrounded by tooth structures at the rim.
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Octopods have eight arms, which are similar to a squid's but they lack teeth. They also do not have tentacles or fins and feed on a variety of fish and invertebrates.
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Nautiloids have external shells unlike coleoids like octopus or squid. Their heads are covered with 60-90 tentacles coated with a sticky substance that helps them to adhere to objects. Like other cephalopods, nautiloids move by means of jet propulsion. Water is drawn in and forced out, pushing the animal shell first through the water. |