Shell rudiment. Small internal structure made of calcium carbonate secreted by the mantle; some species do not have shells. Crop. Large sac located where food is held before being digested in the stomach.

What is a Hectocotylus used for?

A hectocotylus (plural: hectocotyli) is one of the arms of male cephalopods that is specialized to store and transfer spermatophores to the female.

Where is the shell in an octopus?

Its shell is inside of its body. Its shell has chambers and the shell has even evolved to protect its brain. That protection is an advantage. It's also an advantage for the octopus to have the shell inside of the body.

Does octopus have shell?

Most people are familiar with octopuses in the Incirrata group. They have soft bodies and no internal shell (or in some species two small rods made of cartilage), which allows them to squeeze their bodies through unimaginably tight spaces.

What are cephalopod shells?

A shell's shape. Cephalopods with shells on the outside—like some extinct species and the living nautilus—might resemble snails. But, while snail shells have just one continuous space inside, the interior of cephalopod shells is divided by walls, or septa.

M06T1.1 - Intro to Linux - Bash Redirections - Rudiments

20 related questions found

Where are cephalopods shells?

Most modern Cephalopods keep their shell inside of their bodies, like the squid and cuttle fish. The only modern cephalopod to have an external shell is the Nautilus.

What does the word cephalopods mean?

: any of a class (Cephalopoda) of marine mollusks including the squids, cuttlefishes, and octopuses that move by expelling water from a tubular siphon under the head and that have a group of muscular usually sucker-bearing arms around the front of the head, highly developed eyes, and usually a sac containing ink which ...

Why does an octopus have 9 brains?

Octopuses have 3 hearts, because two pump blood to the gills and a larger heart circulates blood to the rest of the body. Octopuses have 9 brains because, in addition to the central brain, each of 8 arms has a mini-brain that allows it to act independently.

Why did octopus lose its shell?

The evolutionary pressures favored being nimble over being armored, and cephalopods started to lose their shells, according to Mr. Tanner. The adaptation allowed them to outcompete their shelled relatives for fast food, and they were able to better evade predators.

Can humans eat octopus?

People of some cultures eat octopus. The arms and sometimes other body parts are prepared in various ways, often varying by species and/or geography. Octopuses are sometimes eaten or prepared alive, a practice that is controversial due to scientific evidence that octopuses experience pain.

Is octopus A squid?

You wouldn't be alone if you thought the octopus and squid were the same animals. ... They are cousins—both part of the group cephalopoda—a group of marine mollusks that include squid, octopus, nautilus, and snails. The largest cephalopod is the giant squid and the smallest being the pygmy squid.

Do freshwater octopuses exist?

Octopuses do not stay in freshwater as their home. No species of freshwater octopus is known. ... However, some "freshwater" octopus can be found in rivers of North America but they are hard to find. The freshwater octopus is a cephalopod, medium in size and about 2-3 feet long.

Why are octopuses invertebrates?

The octopus is an invertebrate, meaning that it does not have a backbone. Octopuses, squid, cuttlefish, and nautiluses make up the cephalopod group (cephalopoda, from the Latin for “head-foot”).

Does hectocotylus regrow?

In male cephalopods, an arm called the hectocotylus is adapted to deliver sperm to the female. ... This arm breaks off from the male during copulation and stays lodged in the female. The hectocotylus regenerates after the mating episode.

How does a hectocotylus work?

When a tiny male argonaut encounters a female, he ruptures a pouch containing his specialized hectocotylus. He loads his arm with sperm, then detaches it from his body. At this stage, the hectocotylus is independent, and the male can pass it over to the female or he can just let the arm swim to the female on its own.

Do octopuses dementia?

Both male and female Pacific octopuses experience this dementia-like state of being. Males will experience this alone, very soon after mating. Females, on the other hand, will lay eggs and faithfully tend to them while going through senescence. ... The last sign of senescence is the appearance of white lesions on the skin.

What did squid evolved from?

Until now the origins of cephalopods, which evolved from ancient marine molluscs with shells, have been shrouded in mystery. ...

How do octopus break shells?

The octopus has a veritable Swiss Army knife of tools located inside its mouth to pry open the shells it can't open with its tentacles. Directly inside its mouth, it has a hard retractable beak similar to a parrot's. This beak is useful for breaking open clam shells and tearing apart flesh.

What animal has 32 brains?

Leech has 32 brains. A leech's internal structure is segregated into 32 separate segments, and each of these segments has its own brain. Leech is an annelid. They have segments.

What animal have 2 Hearts?

An octopus has one main, systemic heart that pumps blood to the whole of its body. But it also has two additional hearts, responsible for pumping blood over each of its gills.

What animal has no brain?

There is one organism that has no brain or nervous tissue of any kind: the sponge. Sponges are simple animals, surviving on the sea floor by taking nutrients into their porous bodies.

Do all mollusks have shells?

Mollusks usually have a shell (although some do not). Mollusks also have an extension of the body wall called the mantle. This portion of the animal's anatomy is responsible for secreting the shell. The mantle encloses the mantle cavity which contains the Ctenidia (gills), anus and excretory pores.

What is the correct about cephalopods?

What Makes a Cephalopod? All cephalopods have either arms or tentacles, have blue-colored blood, and have the ability to use propulsion to help them move swiftly when needed. They use gills to breathe and are invertebrates (lack backbones).

What does cephalopod mean in Latin?

cephalopod (n.)

one of a class of mollusks notable for having tentacles attached to a distinct head, 1825, from French cephalopode, from Modern Latin Cephalopoda (the class name), from Greek kephalē "head" (see cephalo-) + pod-, stem of pous "foot" (from PIE root *ped- "foot").