The water flea known as Cypris.

Water Flea

The water flea known as Cypris.

The water flea known as Daphnia.

Water Flea

The water flea known as Daphnia.

The water flea known as Cyclops.

Water Flea

The water flea known as Cyclops.

The amphipod, Gammarus ornatus.

Gammarus Ornatus

The amphipod, Gammarus ornatus.

Hermit crabs find vacant shells to make into their homes, seeking larger shells as it grows.

Hermit Crab

Hermit crabs find vacant shells to make into their homes, seeking larger shells as it grows.

"[The paguridae] includes the Hermit or Soldier Crab, <em>Pagurus Bernardus</em>, the abdominal portion of whose body is quite soft, forming a sort of cylindrical fleshy mass behind the shelly cephalothorax. As the comfort of the animal would be materially interfered with were this soft, worm-like appendage exposed to be grabbed at by every passing fish who might take a fancy to it, he usually seeks some shelter for its tail, and the habitation selected is generally the empty shell of some univalve mollusk." &mdash; Goodrich, 1859

Hermit-crab

"[The paguridae] includes the Hermit or Soldier Crab, Pagurus Bernardus, the abdominal portion…

"The <em>Parthenope horrida</em>, a native of the Atlantic and Indian Oceans, is covered with the most grotesque ornaments." &mdash; Goodrich, 1859

Parthenope horrida

"The Parthenope horrida, a native of the Atlantic and Indian Oceans, is covered with the most…

Isopods are one of the most diverse orders of Crustaceans, with many species living in all environments, and are common in shallow marine waters.

Isopod

Isopods are one of the most diverse orders of Crustaceans, with many species living in all environments,…

Entoniscus parasites is a parasitic isopod that feeds off and eventually replaces the tongues of fish and crabs.

Parasitic Isopod

Entoniscus parasites is a parasitic isopod that feeds off and eventually replaces the tongues of fish…

This illustration shows an isopoda. These are one of the most diverse orders of Crustaceans, with many species living in all environments, and are common in shallow marine waters.

Isopods

This illustration shows an isopoda. These are one of the most diverse orders of Crustaceans, with many…

External features of the lobster.

Lobster

External features of the lobster.

Lobsters have five pair of legs. The first pair are modified into claws for defense.

Lobster

Lobsters have five pair of legs. The first pair are modified into claws for defense.

Common lobster. I. first pair of legs; 2 and 3. second and third pairs of legs; 4 and 5. last two pair of legs; a smaller antennae; ga greater antennae; ca carapace.

Lobster

Common lobster. I. first pair of legs; 2 and 3. second and third pairs of legs; 4 and 5. last two pair…

"Bilaterally symmetrical bodies composed of a series of rings or segments, each of which bears a pair of jointed appendages, or limbs; a well developed and symmetrical nervous system of many connected ganglia. The lower arthropoda are the crustaceans, such as the lobster." &mdash; Hinman, 1888

Lobster

"Bilaterally symmetrical bodies composed of a series of rings or segments, each of which bears a pair…

The lobster, a crustacean.

Lobster

The lobster, a crustacean.

Lobster claw.

Lobster

Lobster claw.

An illustration of a lobster fossil.

Lobster Fossil

An illustration of a lobster fossil.

"The Spiny Lobster, <em>Palinurus vulgaris</em>, which may be taken as the type of the family, often weighs as muich as twelve or fifteen pounds. It was in great esteem among the ancient Romans, who denominated it <em>Locusta</em>. &mdash; Goodrich, 1859

Spiny lobster

"The Spiny Lobster, Palinurus vulgaris, which may be taken as the type of the family, often…

Wood-lice are commonly found under stones or in crevices of old walls. When disturbed, they curl up to protect their soft abdomens.

Wood Louse

Wood-lice are commonly found under stones or in crevices of old walls. When disturbed, they curl up…

Wood-lice are commonly found under stones or in crevices of old walls. When disturbed, they curl up to protect their soft abdomens.

Wood Louse

Wood-lice are commonly found under stones or in crevices of old walls. When disturbed, they curl up…

"Megalops of Cancer irroratus." &mdash; Galloway

Megalop

"Megalops of Cancer irroratus." — Galloway

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting tail. The body of the crab in its first larval stage is composed of short, globular portion, furnished with conspicuous long spines and a relaively long, jointed tail. This is call the zo&euml;a stage.

Metamorphosis of a Crab

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting…

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting tail. After the first stage, the zo&euml;a changes into a stage called the megalops, which has many characteristics of the adult crab condition. In this stage the crab looks very much like a tiny lobster or shrimp.

Metamorphosis of a Crab

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting…

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting tail. After the first stage, the zo&euml;a changes into a stage called the megalops, which has many characteristics of the adult crab condition. In this stage the crab looks very much like a tiny lobster or shrimp. In the final stage the tail disappears and the body widens.

Metamorphosis of a Crab

Crabs are decapod crustaceans of the infraorder Brachyura, which generally have a very short projecting…

"Norway Lobsters have the eyes uniform and the two last rings of the thorax movable."

Nephrops Norvegicus

"Norway Lobsters have the eyes uniform and the two last rings of the thorax movable."

"The Hermit or Soldier Crab is perhaps the oddest and most curious of the Crustaceans." Hermit Crabs seek out a shell to inhabit and will kill a living mollusk to take its home.

Pagurus Bernhardus, In the Shell

"The Hermit or Soldier Crab is perhaps the oddest and most curious of the Crustaceans." Hermit Crabs…

"The Hermit or Soldier Crab is perhaps the oddest and most curious of the Crustaceans." Hermit Crabs seek out a shell to inhabit and will kill a living mollusk to take its home.

Pagurus Bernhardus, Out of the Shell

"The Hermit or Soldier Crab is perhaps the oddest and most curious of the Crustaceans." Hermit Crabs…

"The common crayfish. Crustaceans are nearly all carnivorous. <em>a</em>, left outward root-jaw"

Palinurus Vulgaris

"The common crayfish. Crustaceans are nearly all carnivorous. a, left outward root-jaw"

"Among some Crustaceans there is neither thorax, nor abdomen, nor head, but all three form only one mass, often short and squat, as in the Four-horned Spider-crab."

Pisa Tetraodon

"Among some Crustaceans there is neither thorax, nor abdomen, nor head, but all three form only one…

a: external antenna;b: external foot-jaw;c: tail or abdomen.

Portunus Variegatus, male

a: external antenna; b: external foot-jaw; c: tail or abdomen.

"The Purse Crab, <em>Birgus Latro</em> is a very curious species found in Amboyna and some of the adjacent islands. They inhabit the fissures of rocks along the sea-shore by day and come forth at night to search for food along the beach. When they meeta person they set up their claws in a threatening manner and snap their pincers and retreat backward. The natives say they climb the cocoanut-trees to get the cocoanuts." &mdash; Goodrich, 1859

Purse-crab

"The Purse Crab, Birgus Latro is a very curious species found in Amboyna and some of the adjacent…

"Alpheus-A genus of macrurous decapodous crustaceans, the type of the family Alpheid&aelig;."-Whitney, 1902

Red Shrimp

"Alpheus-A genus of macrurous decapodous crustaceans, the type of the family Alpheidæ."-Whitney,…

"A parasitic isopod crustacean, Aega psora, and some similar forms." -Whitney, 1911

Salve Bug

"A parasitic isopod crustacean, Aega psora, and some similar forms." -Whitney, 1911

The schizopod stage of a prawn in the Penaeus genus of crustaceans.

Schizopod

The schizopod stage of a prawn in the Penaeus genus of crustaceans.

The Speckled Sea Louse (Eurydice pulchra) is a parasitic crustacean in the Cirolanidae family.

Speckled Sea Louse

The Speckled Sea Louse (Eurydice pulchra) is a parasitic crustacean in the Cirolanidae family.

Pantopoda, or Sea Spiders, are a remarkable group of Arthropod animals, perhaps intermediate between Crustaceans and Arachnids. They are spider-like organisms, having four well-developed walking legs, often of great length. The body consists of an unsegmented proboscis, a trunk of four segments, and an unsegmented abdomen. There are no gills -- a point of distinction from the crustaceans; but the number of appendages in front of the legs is different from that of the true spiders. In the more typical forms there are three appendages in front of the legs -- first a small pair of chelate limbs, then two pairs of slender appendages. The first of these are used like the chelae in food getting; and the second seem to be functionless in the female, while in the male they carry the eggs. In the common shore sea spider <i> (Pycnogonum littorale) </i> , however, the two anterior appendages are absent in both sexes, and the third or egg-carrying pair are present only in the male. This form is found beneath stones, and is of a yellowish color, with thick, knobbed legs. Another common form is <i> Phoxichilidium femoratum </i> , which is of a pink color, has very long legs, and is commonly found on bright-colored weeds in shore pools. A representative American species is <i> Phoxichilidium maxillare </i> , which spreads about an inch and varies in color from deep brown to almost white. It is commonly found in shore pools; and its young live for a time withing hydroids. It is in the ocean abysses that the sea spiders reach their maximum size. One deep-sea form <i> (Colossendeis gigas) </i> has a span of nearly two feet from tip to tip of the legs. There is a metamorphosis in development in the sea spiders, the larvae having at first three pairs of appendages.

Sea Spider

Pantopoda, or Sea Spiders, are a remarkable group of Arthropod animals, perhaps intermediate between…

"The bodies of these animals are compressed laterally, and curved upon the sides; the eyes are immovable, their feet are directed partly forwards and partly backwards." &mdash; Williams, 1889

Shore-jumper

"The bodies of these animals are compressed laterally, and curved upon the sides; the eyes are immovable,…

Shrimp are a marine crustacean largely used as food.

Shrimp

Shrimp are a marine crustacean largely used as food.

"They are distinguished by the possession of a large oval or triangular appendage which covers the base of the first joint of the outer antennae." &mdash; Goodrich, 1859

Shrimp

"They are distinguished by the possession of a large oval or triangular appendage which covers the base…

"Shrimp is a popular name for any individual of the genus Crangon, allied to lobster, crayfish, and prawn. The common shrimp about two inches long, greenish-gray dotted with brown, is esteemed as an article of food; other species, from warmer latitudes, are equally prized. They are usually taken by a net."&mdash;(Charles Leonard-Stuart, 1911)

Shrimp

"Shrimp is a popular name for any individual of the genus Crangon, allied to lobster, crayfish, and…

A common shrimp, a genus of the decapod Crustacea.

Shrimp

A common shrimp, a genus of the decapod Crustacea.

A small crustacean.

Shrimp

A small crustacean.

The Common Shrimp (Crangon crangon) is a shrimp fished mainly in the North Sea. The species is also known as the Brown Shrimp or the Sand Shrimp with the synonym Crangon vulgaris.

Common Shrimp

The Common Shrimp (Crangon crangon) is a shrimp fished mainly in the North Sea. The species is also…

The Fairy Shrimp (Branchipus diaphanus) is a species of crustacean belonging to the Anostraca order.

Fairy Shrimp

The Fairy Shrimp (Branchipus diaphanus) is a species of crustacean belonging to the Anostraca order.

An adult shrimp.

Mature shrimp

An adult shrimp.

Palaemonetes vulgaris or the common shore shrimp.

Shore Shrimp

Palaemonetes vulgaris or the common shore shrimp.

the Isopoda have a body flattened from above, and bear gills on the abdominal appendages, as in the sow bug.

Sow Bug

the Isopoda have a body flattened from above, and bear gills on the abdominal appendages, as in the…

"A terrestrial crustacean abundant everywhere under logs and stones during most of the year." &mdash;Davison, 1906

Sow Bug

"A terrestrial crustacean abundant everywhere under logs and stones during most of the year." —Davison,…

"In these the back is usually covered with spines and hairs. They generally live in deep water, and rarely approach the shore." &mdash; Goodrich, 1859

Spinous spider-crab

"In these the back is usually covered with spines and hairs. They generally live in deep water, and…

"The <em>Eriphea spinifrons</em>, for instance, distributed in nearly all seas, has the front covered with numerous sharp spines." &mdash; Goodrich, 1859

Eriphia spinifrons

"The Eriphea spinifrons, for instance, distributed in nearly all seas, has the front covered…

The Squat Lobster (the name often used for Galathea) is a genus of decapod crustacea. The body is lobster-like, but is broad and somewhat flattened, the tail being habitually carried in a bent position. Several species inhabit the northeastern Atlantic shores.

Squat Lobster

The Squat Lobster (the name often used for Galathea) is a genus of decapod crustacea. The body is lobster-like,…

"The typical genus <em>Aquilla</em> is frequently called the <em>Sea-Mantis</em>. Some of them attain the length of a foot or more, but their average size is about three to four inches." &mdash; Goodrich, 1859

Squilla

"The typical genus Aquilla is frequently called the Sea-Mantis. Some of them attain…

"The common species of Squilla is <em>squilla mantis</u>, so called for its supposed resemblance to the insect mantis."&mdash;Finley, 1917

Squilla

"The common species of Squilla is squilla mantis, so called for its supposed resemblance to the

"The Whale-Louse, <em>Cyamus seti</em>, is found on whales along our coasts." &mdash; Goodrich, 1859

Whale-louse

"The Whale-Louse, Cyamus seti, is found on whales along our coasts." — Goodrich, 1859

"The family Oniscidae, including the well-known Wood-Louse, <em>Oniscus murarius</em>, and many similar animals, are characterized by the adaptation of their members to a terrestrial existence." &mdash; Goodrich, 1859

Wood-louse

"The family Oniscidae, including the well-known Wood-Louse, Oniscus murarius, and many similar…

Woodlice are crustaceans with a rigid, segmented, long exoskeleton and fourteen jointed limbs. They form the suborder Oniscidea within the order Isopoda, with over 3,000 known species.

Woodlouse

Woodlice are crustaceans with a rigid, segmented, long exoskeleton and fourteen jointed limbs. They…

This illustration shows a worm. Worms have an elongated soft-body. The most famous is the earthworm, but there are hundreds of thousands of different species that live in a wide variety of habitats other than soil.

Worms

This illustration shows a worm. Worms have an elongated soft-body. The most famous is the earthworm,…

The first free-swimming larval stage of crustaceans.

Zoea

The first free-swimming larval stage of crustaceans.

An illustration of a Zoea of common shoe-crap in its second stage. r, Rostral spine; s, Dorsal spine; m, Maxillipeds; t, Buds of thoracic feet; a, Abdomen.

Zoea

An illustration of a Zoea of common shoe-crap in its second stage. r, Rostral spine; s, Dorsal spine;…

"The lowest division of articulate animals is the Crustacea. Their name signifies a hard crust of covering, with which the animals are protected."

Zoea Taurus

"The lowest division of articulate animals is the Crustacea. Their name signifies a hard crust of covering,…