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Cephalopod limb facts for kids

Kids Encyclopedia Facts
Arm of Illex illecebrosus with two rows of suckers along its length
Tentacle of Illex illecebrosus with a distal tentacular club (right)
Giant squid NTNU 4
Serrated suckers of a giant squid
Img octopus arm and suckers 057513
Octopus arm with two rows of suckers

All cephalopods possess flexible limbs extending from their heads and surrounding their beaks. These appendages have been termed arms, legs or tentacles.

Description

Arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends. Barring a few exceptions, octopuses have eight arms and no tentacles, while squid and cuttlefish have eight arms (or two "legs" and six "arms") and two tentacles. The limbs of nautiluses, which number around 90 and lack suckers altogether, are called tentacles.

Suckers

Cephalopod limbs bear numerous suckers along their ventral surface as in octopus, squid and cuttlefish arms and in clusters at the ends of the tentacles (if present), as in squid and cuttlefish.

Each sucker is usually circular and bowl-like and has two distinct parts: an outer shallow cavity called an infundibulum and a central hollow cavity called an acetabulum.

Both of these structures are thick muscles, and are covered with a chitinous cuticle to make a protective surface. Suckers are used for grasping plants, catching prey and for locomotion.

Variability

Cephalopod limbs and the suckers they bear are shaped in many distinctive ways, and vary considerably between species.

Suckers of octopus by steve lodefink
Octopus suckers
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Cephalopod limb Facts for Kids. Kiddle Encyclopedia.