Class CephalopodaClass Cephalopoda

The “Head-Footed” MollusksThe “Head-Footed” Mollusks

ZoologyZoology

Cephalopods Walk on Cephalopods Walk on Their Heads….Their Heads….

The Class The Class Cephalopoda Cephalopoda includes the includes the octopus octopus , , squid, squid, Nautilus Nautilus , devil fish, and , devil fish, and Cuttlefish Cuttlefish ..

Cephalopoda comes from the Greek words Cephalopoda comes from the Greek words kephalekephale meaning meaning head head and and podospodos meaning meaning foot foot . .

Their modified foot is actually concentrated in the Their modified foot is actually concentrated in the head head or cephalic region of their body. It forms a funnel or cephalic region of their body. It forms a funnel that that rapidly removes rapidly removes water from the water from the mantle mantle cavity cavity of the body when the cephalopod moves.of the body when the cephalopod moves.

The anterior portion of the body is drawn into a The anterior portion of the body is drawn into a circle circle or or crown crown of tentacles. of tentacles.

Do These Tentacles Make Do These Tentacles Make Me Look Fat….Me Look Fat….

Cephalopods range Cephalopods range upward in size from upward in size from 2 cm 2 cm ..

The largest invertebrate The largest invertebrate known on earth is the known on earth is the giant giant squid squid (Architeuthis .)(Architeuthis .) It It can reach can reach 60 feet60 feet in length in length and weighs nearly a and weighs nearly a a ton a ton ..

The giant squid has the The giant squid has the largest largest eyes in the eyes in the animal kingdom. They are animal kingdom. They are 25 cm 25 cm in diameter! in diameter!

Umm…Have You Seen My Umm…Have You Seen My Shell?Shell?

Most members of Most members of Cephalopoda do not have a Cephalopoda do not have a visible visible shell shell . .

The The Nautilus Nautilus is the only is the only member of this class that still member of this class that still has a shell. It uses the has a shell. It uses the gas gas chambers chambers in its shell to in its shell to remain buoyant in the water.remain buoyant in the water.

The The squid squid has a tiny has a tiny remnant remnant shell left on the shell left on the inside of its mantleinside of its mantle

The The octopus octopus has lost its has lost its shell completely over the last shell completely over the last time.time.

Moving On Up…Moving On Up…

Cephalopods are Cephalopods are very very fast fast and and agile agile swimmers. swimmers.

They swim by They swim by expelling water from expelling water from their their mantle mantle ..

Judge Me By My Book…Not Judge Me By My Book…Not My CoverMy Cover Cephalopods are very Cephalopods are very

complex complex animals animals . . They have complex They have complex

circulatory circulatory systems made systems made with a closed series of with a closed series of vessels. vessels.

OctopusesOctopuses_ have very _ have very complex complex nervous systems. nervous systems. They are capable of They are capable of learned learned behaviors. Their behaviors. Their eyes eyes are are very very complexcomplex with a lens, with a lens, cornea cornea , and retina. They , and retina. They can see in the water better can see in the water better than than a human a human . .

The The octopusoctopuscan also use its can also use its tentacles to detect tentacles to detect textures textures in objects.in objects.

Defending My Domain….Defending My Domain….

Cephalopods exhibit many Cephalopods exhibit many complex behaviors. complex behaviors.

The The octopus octopus and and squid squid can expel can expel ink called sepiaink called sepia as a defensive behavior to as a defensive behavior to fool and evade fool and evade predators predators ..

Octopus use their sharp Octopus use their sharp beaks beaks and and strong strong tentacles tentacles to capture and to capture and harm prey. They are one harm prey. They are one of the ocean’s most of the ocean’s most powerful predators.powerful predators.