Class-Cephalopoda

__Class Cephalopoda The Head-Feet Complex__ Cephalopods are marine invertebrates with arms or tentacles connected to a prominent head. Like Bivalves, cephalopods are bilaterally symmetrical. They have mantle cavities in which jet propulsion takes place. "Cephalopoda" comes from the Greek "kephalópoda", meaning "head-feet". (A drawing of cephalopods depicted by German biologist Ernst Haeckel in 1904.)

__The Cephalopods __: The Octopus The Giant Squid

__The Octopus__: Octopuses are aquatic animals with notable bilateral symmetry; they have two eyes and four pairs of legs. They also have sharp beaks located at their mouths in the center of the legs. Their legs have suckers on them for attachment of objects or prey. Since octopus have no skeleton, they are quite flexible and can squeeze through tight spaces. The word "octopus" comes from the Greek "oktapous", meaning "eight-legged". Octopuses usually hang around coral reefs around the seas.

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__The Giant Squid__: The giant squid is truly a GIANT. It can grow as big as 13 feet for females and 10 feet for males. The giant squid's cousin, the colossal squid, is the world's biggest invertebrate. The only predator of giant squids is the sperm whale, and perhaps, other giant squids. Giant squids are usually found near continental and island slopes in the North Atlantic Ocean, but they're all over the oceans. Giant squids phenotypically resemble octopuses, but the only obvious distinction between a squid and an octopus is that the suckers of squid look like hooks, while octopus have simple suckers. Giant Squids are cannibals and remains of giants squids had been found inside of other giant squids.

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 __LIFE STYLE: Locomotion__ Octopuses move either by crawling or swimming. They crawl by moving their legs about on either hard or soft surfaces. They can also swim by propulsion; they jet out water and rocket forward. Squids, too swim by jet propulsion.

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__Feeding__ Octopuses usually eat crabs, crayfish, and small mollusks during its hunting at night. They grab and stun prey with their tentacles, and proceed to attack the prey with their sharp beaks. Giant Squids are similar in that eating fashion, as they grab deep-sea fish with two tentacles, and uses its radula to shear its prey before swallowing. media type="custom" key="5622399" width="242" height="242"

__Reproduction__ -Octopuses reproduce in a strange fashion. The male octopus uses a specialized arm called the hectocotylus to insert spermatophores (sperm packets) into the female. After fertilization, the female lays roughly 200,000 eggs, and hangs them in her lair. She then spends a one-month period caring for the eggs until they hatch, often neglecting to eat, but sometimes eats her own arms. After hatching, the mother usually dies to predator attacks. The larvae drifts with surrounding plankton and feeds off of larval crabs and starfish until maturity. However, most of those do not make it, as they are eaten by plankton predators. -Not much is known about the reproductive cycle of giant squids. It is known that females have an ovary and produces almost 11 pounds worth of eggs; the male has spermatophores that are stored in a sac (called the Needham's sac) at the end of its 90-cm long penis, which extends from its mantle cavity. However, how the giant squids mate is unknown.

__Fun Facts__ -The colossal squid, the giant squid's cousin, can range from 39-46 feet long! -Octopuses can fit through 1-inch diameter holes. media type="custom" key="5622541" width="468" height="468"

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