Amphipoda include over 7000 described species of small, shrimp-like crustaceans. Most amphipods are marine, although a few live in freshwater or are terrestrial.

Amphipod

Amphipoda include over 7000 described species of small, shrimp-like crustaceans. Most amphipods are…

Scene showing various animals of the Division <em>Articulata</em>.

Articulata

Scene showing various animals of the Division Articulata.

An adult barnacle

Barnacle

An adult barnacle

The Goose Barnacle has a body resembling a clam, attached by a soft, flexible stalk to some solid object.

Barnacle

The Goose Barnacle has a body resembling a clam, attached by a soft, flexible stalk to some solid object.

The barnacle is a type of fixed crustacean.

Barnacle

The barnacle is a type of fixed crustacean.

"Acorn barnacle, with arms extended." -Cooper, 1887

Acorn Barnacle

"Acorn barnacle, with arms extended." -Cooper, 1887

A species of goose necked barnacles, a crustacean known for attaching itself to objects and other animals.

Goose Necked Barnacle

A species of goose necked barnacles, a crustacean known for attaching itself to objects and other animals.

"The Common Barnacle, <em>Lepas anatifera</em>, perhaps the best-known example of the order, generally selects floating objects for this purpose, and frequently covers the bottoms of ships to such an extent as to even impede their progress through the water. It adheres by a flexible stalk, which possesses great contractile power. The shell is usually composed of two triangular pieces on each side, and is closed by another elongated piece on the back." &mdash; Goodrich, 1859

Barnacles

"The Common Barnacle, Lepas anatifera, perhaps the best-known example of the order, generally…

"The trilobite's general form is shown in the annexed figure of the <em>Calymene Blumenbachii</em>; they possessed well-formed, compound, faceted eyes, which are frequently well-preserved in the fossil state. The body is usually divided into three regions, of which the first and last are commonly in the form of the semicircular plates, while the middle portion exhibits distinct segmentation, and by its flexibilty enabled the animal to double itself up in the manner of the common wood-louse." &mdash; Goodrich, 1859

Calymene

"The trilobite's general form is shown in the annexed figure of the Calymene Blumenbachii;…

The amphipod, Caprella geometrica.

Caprella Geometrica

The amphipod, Caprella geometrica.

"Epistylis anastatica, magnified, growing in seven zo&ouml;dendria or dendriform colonies of zo&ouml;ids, on an entomostracous crustacean. (Two detached individuals on the left are much more highly magnified.)" -Whitney, 1911

Ciliate

"Epistylis anastatica, magnified, growing in seven zoödendria or dendriform colonies of zoöids,…

Diagram of the circulation in a crustacean. Labels: a, branchial; b, somatic circulation. On the right side is the heart with is single cavity, and on the left the venous lacunae.

Circulation of a Crustacean

Diagram of the circulation in a crustacean. Labels: a, branchial; b, somatic circulation. On the right…

Circulatory and respiratory system of the crayfish. C-heart with three pairs of ostia; Ps, pericardium; Ac, cephalic aorta; A, ab, abdominal aorta; As, sternal artery. The arrows indicate the direction of the flow.

Circulatory and Respiratory System of a Crayfish

Circulatory and respiratory system of the crayfish. C-heart with three pairs of ostia; Ps, pericardium;…

Copepoda, an order of Crustacea. A, cyclops quiadricornis; b, c, d, stages of growth in larvae.

Copepoda

Copepoda, an order of Crustacea. A, cyclops quiadricornis; b, c, d, stages of growth in larvae.

"The anterior feet are about the length of the body. The other feet terminate in an elongated claw, which is straight-pointed."

Corystes Cassivelaunus, female

"The anterior feet are about the length of the body. The other feet terminate in an elongated claw,…

"The Long-clawed Crab is remarkable for its long antennae, which considerably exceed the length of the body."

Corystes Cassivelaunus, male

"The Long-clawed Crab is remarkable for its long antennae, which considerably exceed the length of the…

Crabs have the same essentail structure as crayfishes and lobsters.

Crab

Crabs have the same essentail structure as crayfishes and lobsters.

This illustration shows a crab, a species of cancer. Crabs are decapod crustaceans with thick exoskeletons.

Crab

This illustration shows a crab, a species of cancer. Crabs are decapod crustaceans with thick exoskeletons.

"Transformations of the Crab: 1, young crab, or zoea, magnified; 2, young crab, in a more advanced stage, magnified; 3, young crab, in a more advanced stage, natural size; 4, young crab, when it has assumed its more perfect form, magnified; 5, young crab, when it has assumed its more perfect form, natural size." &mdash; Chambers' Encyclopedia, 1875

Crab

"Transformations of the Crab: 1, young crab, or zoea, magnified; 2, young crab, in a more advanced stage,…

Eriphia laevimana is a crustacean in the Cancridae family of crabs.

Crab

Eriphia laevimana is a crustacean in the Cancridae family of crabs.

A crab dancing on a rock with its arms spread out.

Crab Dancing

A crab dancing on a rock with its arms spread out.

"Nervous system of shore-crab (Carcinus manas). br., The supra-oesophageal mass; g., gullet surrounded by gr., the gullet ring; m., the sub-oesophageal mass representing a fusion of the thoracic ganglia of the crayfish, and giving off nerves to the limbs; behind it is a short strand representing the abdominal ganglia of the crayfish. a1., antennules; a2., antennae; e., eye." -Thomson, 1916

Shore Crab Nervous System

"Nervous system of shore-crab (Carcinus manas). br., The supra-oesophageal mass; g., gullet surrounded…

A crab standing on a rock singing.

Crab Standing

A crab standing on a rock singing.

"Zoaea of common shore-crab (Carcinus manas). The appendages are numbered; c., gills; i., alimentary canal." -Thomson, 1916

Shore Crab Zoaea

"Zoaea of common shore-crab (Carcinus manas). The appendages are numbered; c., gills; i., alimentary…

The Dungeness crab is a species of crab that inhabits eelgrass beds and water bottoms from the Aleutian Islands in Alaska to Santa Cruz, California. Its binomial name, Cancer magister, simply means "master crab" in Latin. They measure as much as 25 cm (10 inches) in some areas off the coast of Washington, but typically are under 20 cm (8 inches). They are a popular delicacy, and are the most commercially important crab in the Pacific Northwest, as well as the western states generally.

Dungeness Crab

The Dungeness crab is a species of crab that inhabits eelgrass beds and water bottoms from the Aleutian…

The edible crab (Cancer pagurus) is a species of crab found in the North Sea, North Atlantic, and the Mediterranean Sea.

Edible Crab

The edible crab (Cancer pagurus) is a species of crab found in the North Sea, North Atlantic, and the…

The Sand Fiddler Crab (Uca pugilator) is a small crustacean in the Ocypodidae family of ghost and fiddler crabs. It was once known as the synonym Gelasimus pugilator.

Sand Fiddler Crab

The Sand Fiddler Crab (Uca pugilator) is a small crustacean in the Ocypodidae family of ghost and fiddler…

When alarmed, the hermit crab withdraws itself wholly into its portable house, closing the mouth of the shell with one of its claws, (Hooker, 1882).

Hermit Crab

When alarmed, the hermit crab withdraws itself wholly into its portable house, closing the mouth of…

"When alarmed, the hermit crab withdraws itself wholly into its portable house, closing the mouth of the shell with one of its claws, "(Hooker, 1882).

Hermit Crab

"When alarmed, the hermit crab withdraws itself wholly into its portable house, closing the mouth of…

Hermit crab in shell of sea snail.

Hermit Crab

Hermit crab in shell of sea snail.

Horseshoe crabs represent an order called Xiphosura, from the fact that the end of the abdomen is furnished with a long sword-like spine.

Horseshoe Crab

Horseshoe crabs represent an order called Xiphosura, from the fact that the end of the abdomen is furnished…

An illustration of an adult horseshoe crab from the dorsal aspect. The horseshoe crab or Atlantic horseshoe crab (Limulus polyphemus) is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs. Horseshoe crabs are most commonly found in the Gulf of Mexico and along the northern Atlantic coast of North America. A main area of annual migration is the Delaware Bay, although stray individuals are occasionally found in Europe.

Horseshoe Crab (Adult)

An illustration of an adult horseshoe crab from the dorsal aspect. The horseshoe crab or Atlantic horseshoe…

An illustration of a young horseshoe crab from the dorsal aspect. The horseshoe crab or Atlantic horseshoe crab (Limulus polyphemus) is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs. Horseshoe crabs are most commonly found in the Gulf of Mexico and along the northern Atlantic coast of North America. A main area of annual migration is the Delaware Bay, although stray individuals are occasionally found in Europe.

Horseshoe Crab (Young)

An illustration of a young horseshoe crab from the dorsal aspect. The horseshoe crab or Atlantic horseshoe…

Crabs have the same essentail structure as crayfishes and lobsters.

Oyster Crab

Crabs have the same essentail structure as crayfishes and lobsters.

"The Red Sea Crab - Lupea Pelagica" &mdash; Goodrich, 1859

Red Sea crab

"The Red Sea Crab - Lupea Pelagica" — Goodrich, 1859

Crabs are ten-footed crustaceans. The abdomen is tucked out of site, so that nothing is visible except the carapace.

Spider-Crab

Crabs are ten-footed crustaceans. The abdomen is tucked out of site, so that nothing is visible except…

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they are closely related. They breathe through feather-like gills and are found in bodies of water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is fresh water running, and which have shelter against predators. Most crawfish cannot tolerate polluted water, although some species such as the invasive Procambarus clarkii are more hardy. Some crayfish have been found living as much as 3 m (10 feet) underground.

Crawfish

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they…

Cross-section of abdomen of crayfish.

Crayfish

Cross-section of abdomen of crayfish.

Longitudinal-section of a crayfish, showing digestive, circulatory, reproductive, excretory, and nervous systems.

Crayfish

Longitudinal-section of a crayfish, showing digestive, circulatory, reproductive, excretory, and nervous…

Nervous system of crayfish.

Crayfish

Nervous system of crayfish.

The arthropod, the freshwater crayfish.

Crayfish

The arthropod, the freshwater crayfish.

Blind crayfish of Mammoth Cave.

Blind Crayfish

Blind crayfish of Mammoth Cave.

A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacean, and is hence distantly related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have two nektonic larval stages. Barnacles are encrusters, attaching themselves permanently to a hard substrate. Shown is a barnacle larva.

Barnacles

A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacean, and…

A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacean, and is hence distantly related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile suspension feeders, and have two nektonic larval stages. Barnacles are encrusters, attaching themselves permanently to a hard substrate. Shown is a developed adult barnacle.

Barnacles

A barnacle is a type of arthropod belonging to infraclass Cirripedia in the subphylum Crustacean, and…

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they are related. They breathe through feather-like gills and are found in bodies of water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is fresh water running, and which have shelter against predators

Crayfish

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they…

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they are related. They breathe through feather-like gills and are found in bodies of water that do not freeze to the bottom; they are also mostly found in brooks and streams where there is fresh water running, and which have shelter against predators. This disscetion of a crayfish shows the following: (b) brain, (h) heart, (i) intestine, (k) kidney, (l) liver, (n) nerve cord, (r) reproductive organ, (s) stomach.

Crayfish

Crayfish, crawfish, or crawdads are freshwater crustaceans resembling small lobsters, to which they…

Cyclops, the representative of a number of lowly forms belonging to the order of Copepods, is one of the commest fresh-water Crustacea. The forward segments of the spindle-shaped body are covered by a large shield or carapace. The feet, are few in number, and like its fabled namesake, it bears an eye in the center of the forehead. Diagram of the cyclops shows the (e.s.) egs, (i) intestine, (ov) reproductive organ.

Cyclops

Cyclops, the representative of a number of lowly forms belonging to the order of Copepods, is one of…

The marine isopod or sand flea (Gammarus) is in the sand, under rocks, and in the seaweed. Many are parasitic upon fishes. Gammarus is an amphipod crustacean genus in the family Gammaridae.

Marine Isopod

The marine isopod or sand flea (Gammarus) is in the sand, under rocks, and in the seaweed. Many are…

The marine isopod or sand flea (Caprella) is an omnivorous feeder that eats detritus, one-celled plants, small invertebrates. It is preyed upon by shrimp, sea anemones and several fish species. Females of some species of skeleton shrimp apparently kill the males after mating using a poisonous claw.

Marine Isopod

The marine isopod or sand flea (Caprella) is an omnivorous feeder that eats detritus, one-celled plants,…

Prawns are crustaceans, belonging to the sub-order Dendrobranchiata. They are similar in appearance to shrimp, but can be distinguished by the gill structure which is branching in prawns (hence the name, dendro="tree"; branchia="gill"), but is lamellar in shrimp.

Prawn

Prawns are crustaceans, belonging to the sub-order Dendrobranchiata. They are similar in appearance…

Scorpions are any arachnid of the order Scorpionida. Unlike the majority of arachnid species, scorpions are viviparous. The young are born one by one, and the brood is carried about on its mother's back until the young have undergone at least one moult. All known Scorpion species possess poison or venom. Scorpions use their venom to kill or paralyze their prey so that it can be eaten; in general it is fast-acting, allowing for effective prey capture.

Scorpion

Scorpions are any arachnid of the order Scorpionida. Unlike the majority of arachnid species, scorpions…

The larger, more useful and more familiar Crustacea belong to the subclass Malacostraca. It comprises such animals as the shrimps, crayfish, lobsters, crabs, and a number of other forms. The simplist of these are the opossum-shrimps (Mysis americana). In general appearance they resemle crayfishes or prawns. They are readily distinguished by the two-branched thoracic feet.

Shrimp

The larger, more useful and more familiar Crustacea belong to the subclass Malacostraca. It comprises…

An isopod crustacean found on whales.

Whale Crustacean

An isopod crustacean found on whales.

"The best-known form of the Copepoda is the genus <em>Cyclops</em>, specimens of whch may be found in every stagnant pool; it is the type of the family Cyclopidae, characterized by the possession of a single eye." &mdash; Goodrich, 1859

Cyclops

"The best-known form of the Copepoda is the genus Cyclops, specimens of whch may be found in…

Cypris, a modern ostracod. Female before sexual maturity, right valve of shell removed to show internal anatomy.

Cypris

Cypris, a modern ostracod. Female before sexual maturity, right valve of shell removed to show internal…

A genus of sea urchines

Diadema

A genus of sea urchines

"A low story between two others of greater height, especially one so treated architecturally that from the exterior it appears to form a single story with the one below it ... Part of House on Boulevard Malesherbes, Paris. E, E, entresol." -Whitney, 1911

Entresol

"A low story between two others of greater height, especially one so treated architecturally that from…

Estheria californica is a species of Branchiopod crustaceans most closely resembling the shrimp.

Estheria

Estheria californica is a species of Branchiopod crustaceans most closely resembling the shrimp.

"The fiddler-crab has one large claw and one small one; the large claw is held in such a manner as to suggest a violin, and the small one in such a position as to represent the bow."

Fiddler-crab

"The fiddler-crab has one large claw and one small one; the large claw is held in such a manner as to…

The Copepoda are represented by the cyclops, or water flea. This form is common in sluggish streams and ditches. This is a female with egg sacs.

Water Flea

The Copepoda are represented by the cyclops, or water flea. This form is common in sluggish streams…