The body of the cuttlefish is soft and covered only with a leathery skin. Its eight arms are very long.

Cuttlefish

The body of the cuttlefish is soft and covered only with a leathery skin. Its eight arms are very long.

Octopus, a mollusk related to the squid. It has eight arms with suckers, arranged around a central soft, baggy body.

Octopus

Octopus, a mollusk related to the squid. It has eight arms with suckers, arranged around a central soft,…

Octopus, a mollusk related to the squid. It has eight arms with suckers, arranged around a central soft, baggy body.

Octopus

Octopus, a mollusk related to the squid. It has eight arms with suckers, arranged around a central soft,…

The squid is the best example of the cephalopod group. It is abundant along the Atlantic coast. Squids swim in schools and feed on young herring and mackerel.

Squid

The squid is the best example of the cephalopod group. It is abundant along the Atlantic coast. Squids…

As the name indicates, the octopus has eight arms instead of ten, as in the squids and cuttles.

Octopus

As the name indicates, the octopus has eight arms instead of ten, as in the squids and cuttles.

Chambered nautilus, showing chambers with soft body in outer chamber. It is closely related to the squids and cuttlefishes, but has the body enclosed in a flat-spiral shell.

Nautilus

Chambered nautilus, showing chambers with soft body in outer chamber. It is closely related to the squids…

Cephalopods are the most highly organized Molluscs. The head is distinct, carrying two large globular eyes, and having the mouth in its center.

Cuttlefish

Cephalopods are the most highly organized Molluscs. The head is distinct, carrying two large globular…

The paper-nautilus is closely related to the Octopus.

Paper Nautilus

The paper-nautilus is closely related to the Octopus.

Part of the cephalopod group. The name cephalopod is derived from two greek words which mean feet on head.

Octopus

Part of the cephalopod group. The name cephalopod is derived from two greek words which mean feet on…

A cuttle fish.

Cuttlefish

A cuttle fish.

A squid.

Squid

A squid.

An egg-cluster of squid.

Squid Egg

An egg-cluster of squid.

"Its length from tail to the end of the tentacles is six feet. The two largest of these are furnished with suckers and hooks, which enable the animal to seize its prey with a powerful grip." — Goodrich, 1859

Hooked squid

"Its length from tail to the end of the tentacles is six feet. The two largest of these are furnished…

"Has the body eight inches long, and the longest tentacles nearly three feet." — Goodrich, 1859

Bonelli's Cheiroteuthis

"Has the body eight inches long, and the longest tentacles nearly three feet." — Goodrich, 1859

"Cephalopoda is a class of mollusks, the highest in organization of the division of the animal kingdom. To this class belong the Nautili, Squids, Cuttle-fish, etc. The Cephalopoda receive their name from having organs of prehension and locomotion attached to the head, an arrangement toward which a gradual approach may be traced in the highest gasteropod mollusks."—(Charles Leonard-Stuart, 1911)

Cephalopoda

"Cephalopoda is a class of mollusks, the highest in organization of the division of the animal kingdom.…

"Giant Squid (Architeuthis dux). (From Report of U.S. Fish Commission, 1884.)-Whitney, 1902

Giant Squid

"Giant Squid (Architeuthis dux). (From Report of U.S. Fish Commission, 1884.)-Whitney, 1902

Cuttlefish are animals of the order Sepiida, and are marine cephalopods, small relatives of squid and nautilus.

Cuttle-fish

Cuttlefish are animals of the order Sepiida, and are marine cephalopods, small relatives of squid and…

A fish with eight arms.

Cuttlefish

A fish with eight arms.

"Spirula peronii, lateral view. d, terminal sucker; f, funnel; s1, s2, projecting portions of the shell, the internal part of which is indicated by dotted lines." -Parker, 1900

Spirula Peronii

"Spirula peronii, lateral view. d, terminal sucker; f, funnel; s1, s2, projecting portions of the shell,…

"Liassic 'Thunder bolt' (Belemnites hastata)." -Taylor, 1904

Belemnite

"Liassic 'Thunder bolt' (Belemnites hastata)." -Taylor, 1904

"Oolitic 'Thunder-bolt' (Belemnites puzosianus)." -Taylor, 1904

Belemnites puzosianus

"Oolitic 'Thunder-bolt' (Belemnites puzosianus)." -Taylor, 1904

"Oolitic 'Thunder-bolt' (Belemnites abbreviatus)." -Taylor, 1904

Belemnites abbreviatus

"Oolitic 'Thunder-bolt' (Belemnites abbreviatus)." -Taylor, 1904

"Belemnites mucronatus." -Taylor, 1904

Belemnites mucronatus

"Belemnites mucronatus." -Taylor, 1904

"Natural flint cast of phragmocone of...Belemnites mucronatus." -Taylor, 1904

Belemnites Fossil

"Natural flint cast of phragmocone of...Belemnites mucronatus." -Taylor, 1904

"Belemnite (restored)." -Taylor, 1904

Belemnite

"Belemnite (restored)." -Taylor, 1904

An upclose view of the arm of a Sepia Tuberculosa.

Arm of Sepia Tuberculosa (Lamarck)

An upclose view of the arm of a Sepia Tuberculosa.

"Cuttlefish are probably the most interesting animals of [the cephalopoda] order. They live for five or six years, and lay eggs, which are large and generally found in clusters, and are known to fishermen as sea-grapes."

Sepia Officinalis (Linnaeus)

"Cuttlefish are probably the most interesting animals of [the cephalopoda] order. They live for five…

"The Common Calmar or Squid. They propel themselves backward through the water with great velocity, driving back the water by means of their funnel."

Loligo Vulgaris, with its pen, or internal bone (Lamarck)

"The Common Calmar or Squid. They propel themselves backward through the water with great velocity,…

"The Common Calmar or Squid. They propel themselves backward through the water with great velocity, driving back the water by means of their funnel."

Loligo Gahi (d'Orbigny)

"The Common Calmar or Squid. They propel themselves backward through the water with great velocity,…

"A very ugly-looking creature, which belongs to the <em>Octopodidae</em> family, is the Octopus."

Octopus Vulgaris (Lamarck)

"A very ugly-looking creature, which belongs to the Octopodidae family, is the Octopus."

"A very ugly-looking creature, which belongs to the <em>Octopodidae</em> family, is the Octopus."

Octopus Macropus (Risso)

"A very ugly-looking creature, which belongs to the Octopodidae family, is the Octopus."

"A very ugly-looking creature, which belongs to the <em>Octopodidae</em> family, is the Octopus."

Octopus Brevipes (d'Orbigny)

"A very ugly-looking creature, which belongs to the Octopodidae family, is the Octopus."

"A very ugly-looking creature, which belongs to the <em>Octopodidae</em> family, is the Octopus."

Octopus Horridus (d'Orbigny)

"A very ugly-looking creature, which belongs to the Octopodidae family, is the Octopus."

This creature, belonging to the <em>Octopodidae</em> family, "changes its color under any exertion, so that the animal at rest and in motion are two different beings."

Pinnoctopus Cordiiformis (Q. & G.)

This creature, belonging to the Octopodidae family, "changes its color under any exertion,…

"In one genera [of the <em>Octopodidae</em> family] the arms are completely united in their whole extent by a thin membrane."

Cirrhoteuthis Mulleri (Eschricht)

"In one genera [of the Octopodidae family] the arms are completely united in their whole extent…

The greater argonaut (Argonauta argo) is a cephalopod and a species of pelagic octopus also known as a paper nautilus.

Greater Argonaut

The greater argonaut (Argonauta argo) is a cephalopod and a species of pelagic octopus also known as…

The Common Cuttlefish (Sepia officinalis) is a mollusc in the Sepiidae family of cephalopods.

Common Cuttlefish

The Common Cuttlefish (Sepia officinalis) is a mollusc in the Sepiidae family of cephalopods.

The Atlantic Bobtail (Sepiola atlantica) is a cephalopod in the Sepiolidae family of bobtail squids.

Atlantic Bobtail

The Atlantic Bobtail (Sepiola atlantica) is a cephalopod in the Sepiolidae family of bobtail squids.

The European Squid (Loligo vulgaris) is a large squid belonging to the family Loliginidae. It occurs abundantly in coastal waters from the North Sea to at least the west coast of Africa. This species lives from sea level to depths of 500 m. The mantle is up to 40 cm long. It is the only species in the subgenus Loligo. There are two subspecies of this squid: the nominate L. v. vulgaris, and the Cape Hope Squid, L. v. reynaudi.

European Squid

The European Squid (Loligo vulgaris) is a large squid belonging to the family Loliginidae. It occurs…

The cephalopods are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of arms or tentacles. Teuthology, a branch of malacology, is the study of cephalopods. The class contains two extant subclasses. In the Coleoidea, the mollusk shell has been internalized or is absent; this subclass includes the octopuses, squid, and cuttlefish. In the Nautiloidea the shell remains; this subclass includes the nautilus. About 786 distinct living species of cephalopods have been identified. Two important extinct taxa are Ammonoidea, the ammonites, and Belemnoidea, the belemnites Cephalopods are found in all the oceans of Earth, at all depths. None of them can tolerate freshwater, but a few species tolerate more or less brackish water.

Cephalopod

The cephalopods are the mollusk class Cephalopoda characterized by bilateral body symmetry, a prominent…

A modern decapod cephalopod with remnant of internal shell only.

European Squid

A modern decapod cephalopod with remnant of internal shell only.

Goniatites are extinct ammonoids, shelled cephalopods related to squid, octopus, and belemnites, that form the order Goniatitida. The goniatites all possessed an external shell, which is divided internally into chambers. The animal lived in the largest of the external chambers, and the internal chambers would have been filled with gas, making the animal buoyant in the water.

Coiled Chambered Shell

Goniatites are extinct ammonoids, shelled cephalopods related to squid, octopus, and belemnites, that…