Virtual Museum of Art | Virtual Museum of History | Virtual Public Library | Virtual Science Center | Virtual Museum of Natural History | Virtual War Museum
   You are in: Museum of Natural History >> Aquatic Hall >> CRAB





American’s Four United Republics: Discovery-Based Curriculum

For More Information go to America's Four United Republics Curriculum


 


Crab-A crustacean of the order Decapoda and suborder Brachyura, characterized by the small size of the abdomen, which resembles a short tail curved under the thora

CRAB

 

CRАВ (AS. krabba, Icel. krabbi, Ger. Krabbe). A crustacean of the order Decapoda and suborder Brachyura, characterized by the small size of the abdomen, which resembles a short tail curved under the thorax, all important viscera being included in the thorax. The term extends also to some of the suborder Anomura (purse-crabs, hermit-crabs, etc.), characterized by a condition of abdomen intermediate between that of the Brachyura and that of the Macrura, or long-tailed decapod crustaceans, such as the lobster, crayfish, etc. All the crabs, besides many other crustaceans, were comprehended in the Linmvan genus Cancer; but the number of species is very great, considerably more than 1000, and the Brachyura alone are now arranged in many genera and families.
 

Different Types of Crabs  Copyright Stan Klos

1. FIDDLER CRAB (Qelaslmus pugnax).
2. HERMIT CRAB I Eupagurus longlcarpus)
3. HERMIT, out of Its borrowed shell, showing reduced and defenseless posterior parts.
4. EASTERN EDIBLE O" BLUE CRAB iCallinectes hastatus).
5. A DEEP-SEA CRAB (North Atlantic) Its arms closed Into Natica héros. a defensive box.
6. COCOANUT CRAB (Blrgus latro).
7. COMMON CRAB OF PACIFIC COAST (Cancer maglster).
8. SPIDER CRAB (Liblnla emarglnata).


These various crabs differ very much in the form of the carapace (the back), which in some is orbicular or nearly so; in some, much broader than it is long; in others, longer than broad; in some, prolonged in front into a kind of beak, etc. ; also in its smoothness, or roughness with hairs, tubercles, or spines; in the length of the legs. etc. The eyes are compound, with hexagonal facets, and are elevated on stalks, which are generally short, but sometimes considerably lengthened, and which have the power of motion, so as to turn the eye in different directions. The first pair of limbs are not vised for locomotion, but exhibit in great perfection the characteristic claws or pincers (chclœ) of the decapod crustaceans. Crabs are inhabitants of almost all seas; most of them, however, are found C'hielly near the coast. Some crabs inhabit fresh water, particularly in the warmer parts of the world; and others, known as land-crabs, live among moist herbage, or burrow in sand or earth. Crabs are generally flesh or carrion eaters, though some forms seem to prefer a vegetarian's diet. They are always active and are noted for running sideways, rather than straight ahead. Some have the last pair of limbs expanded at the extremity into a broad blade for swimming, and some have even all the four pairs of limbs intended for locomotion Unis expanded, and sometimes occur far out at sea.

Crabs, like all arthropods (see Arthropoda), molt or change their shell, not at fixed intervals or seasons, but according to the exigencies of their growth, the change being made with great frequency when they are very young, but rarely in advanced age; indeed, from the mollusks and other animals sometimes found adhering to the carapace, it is inferred that the same covering is sometimes worn for a number of years.

Crabs become interesting in the aquarium, from their readiness in seizing food, their activity in tearing and eating it, and their pugnacity. The number of specimens is apt, however, to be soon diminished by the stronger killing and eating the weaker. Crabs vary greatly in size and color, as might be expected from the great number of species and their wide distribution. The giant crab of Japan (ifacroctiira Kœmpfcri), although only a foot across the disk, which is 18 inches long, has such long legs as occasionally to be 15 to 18 feet from tip to tip of the first pair. The great stone-crab of Tasmania, which has short and very thick legs, has been known to reach a weight of over 30 pounds. On the other hand, many species of crab are only a fraction of an inch across. In color, crabs vary from black to white, through all the colors of the rainbow. Shades of green, blue, and gray are perhaps the most common, but the brightest shades of red and yellow are by no means rare. The sexes of crabs are easily distinguished, as the females arc usually larger, and their abdomens broader anil more oval, while males have the chehe more powerfully developed—notably so in the fiddlers.



Economic Importance of Crabs.—These animals supply food for food-fishes, are of great service as scavengers, and are used as human food in various parts of the world. In the United States the principal crab so used is the blue crab (Callincctcs hautains), hundreds of thousands of which are sent to market every year from the waters of Chesapeake Bay alone. The little pea-crabs (Pinnotheres) often found in oysters (see COMMEN8ALISM) are regarded as a great luxury. In К u ropo the species most frequently used are those of the genus Cancer, especially the great Cancer panurus, and there is no reason why the two eastern American species of this genus, the 'rock' and 'lonah' crabs (qq.v.l. should not he far more utilized as food than they are. To this group belong the principal edible crab of the American Pacific coast (Cancer maaistcr), and others smaller which are eaten by the Chinese, etc. This species usually measures 7 to 9 inches in breadth of body, and abounds from Alaska to Mexico, usually below low-tide level on sandy bottom. Crabs which have just shed their shell, and are covered only by a soft skin, are regarded as best, and are called 'shedders* or 'soft-shelled.'

The ways of fishing are various. Many are taken in wicker traps or 'pots.' baited with ment or offal ; another common method is to sink shallow hoop-nets of coarse material and mesh, which «re baited and hauled up rapidly at intervals, bringing the crabs with them. Hand-line fishing, with bundles of meat to which the crabs cling until lifted out of water, is more a sport than a method of market-fishing; but in the Gulf of Mexico trawls or 'trot-lines' are set in several ways, and vast quantities of crabs are thus taken. They are kept for market in floating pens or 'cars,' and shipped alive packed in wet seaweed. They are also preserved by canning, etc.  -- The New international encyclopaedia, Volume 5 edited by Daniel Coit Gilman, Harry Thurston Peck, Frank Moore Colby: 1920 and Stanley L. Klos 1999


 


Start your search on CRAB.


America's Four United Republics Exhibit - Click Here


Unauthorized Site: This site and its contents are not affiliated, connected, associated with or authorized by the individual, family, friends, or trademarked entities utilizing any part or the subject's entire name. Any official or affiliated sites that are related to this subject will be hyper linked below upon submission and Evisum, Inc. review.

Copyright© 2000 by Evisum Inc.TM. All rights reserved.
Evisum Inc.TM Privacy Policy

Search:

About Us

 

 

Image Use

Please join us in our mission to incorporate America's Four United Republics discovery-based curriculum into the classroom of every primary and secondary school in the United States of America by July 2, 2026, the nation’s 250th birthday. , the United States of America: We The People Click Here

 

Childhood & Family

Click Here

 

Historic Documents

Articles of Association

Articles of Confederation 1775

Articles of Confederation

Article the First

Coin Act

Declaration of Independence

Declaration of Independence

Emancipation Proclamation

Gettysburg Address

Monroe Doctrine

Northwest Ordinance

No Taxation Without Representation

Thanksgiving Proclamations

Mayflower Compact

Treaty of Paris 1763

Treaty of Paris 1783

Treaty of Versailles

United Nations Charter

United States In Congress Assembled

US Bill of Rights

United States Constitution

US Continental Congress

US Constitution of 1777

US Constitution of 1787

Virginia Declaration of Rights

 

Historic Events

Battle of New Orleans

Battle of Yorktown

Cabinet Room

Civil Rights Movement

Federalist Papers

Fort Duquesne

Fort Necessity

Fort Pitt

French and Indian War

Jumonville Glen

Manhattan Project

Stamp Act Congress

Underground Railroad

US Hospitality

US Presidency

Vietnam War

War of 1812

West Virginia Statehood

Woman Suffrage

World War I

World War II

 

Is it Real?



Declaration of
Independence

Digital Authentication
Click Here

 

America’s Four Republics
The More or Less United States

 
Continental Congress
U.C. Presidents

Peyton Randolph

Henry Middleton

Peyton Randolph

John Hancock

  

Continental Congress
U.S. Presidents

John Hancock

Henry Laurens

John Jay

Samuel Huntington

  

Constitution of 1777
U.S. Presidents

Samuel Huntington

Samuel Johnston
Elected but declined the office

Thomas McKean

John Hanson

Elias Boudinot

Thomas Mifflin

Richard Henry Lee

John Hancock
[
Chairman David Ramsay]

Nathaniel Gorham

Arthur St. Clair

Cyrus Griffin

  

Constitution of 1787
U.S. Presidents

George Washington 

John Adams
Federalist Party


Thomas Jefferson
Republican* Party

James Madison 
Republican* Party

James Monroe
Republican* Party

John Quincy Adams
Republican* Party
Whig Party

Andrew Jackson
Republican* Party
Democratic Party


Martin Van Buren
Democratic Party

William H. Harrison
Whig Party

John Tyler
Whig Party

James K. Polk
Democratic Party

David Atchison**
Democratic Party

Zachary Taylor
Whig Party

Millard Fillmore
Whig Party

Franklin Pierce
Democratic Party

James Buchanan
Democratic Party


Abraham Lincoln 
Republican Party

Jefferson Davis***
Democratic Party

Andrew Johnson
Republican Party

Ulysses S. Grant 
Republican Party

Rutherford B. Hayes
Republican Party

James A. Garfield
Republican Party

Chester Arthur 
Republican Party

Grover Cleveland
Democratic Party

Benjamin Harrison
Republican Party

Grover Cleveland 
Democratic Party

William McKinley
Republican Party

Theodore Roosevelt
Republican Party

William H. Taft 
Republican Party

Woodrow Wilson
Democratic Party

Warren G. Harding 
Republican Party

Calvin Coolidge
Republican Party

Herbert C. Hoover
Republican Party

Franklin D. Roosevelt
Democratic Party

Harry S. Truman
Democratic Party

Dwight D. Eisenhower
Republican Party

John F. Kennedy
Democratic Party

Lyndon B. Johnson 
Democratic Party 

Richard M. Nixon 
Republican Party

Gerald R. Ford 
Republican Party

James Earl Carter, Jr. 
Democratic Party

Ronald Wilson Reagan 
Republican Party

George H. W. Bush
Republican Party 

William Jefferson Clinton
Democratic Party

George W. Bush 
Republican Party

Barack H. Obama
Democratic Party

Please Visit

Forgotten Founders
Norwich, CT

Annapolis Continental
Congress Society


U.S. Presidency
& Hospitality

© Stan Klos

 

 

 

 


Virtual Museum of Art | Virtual Museum of History | Virtual Public Library | Virtual Science Center | Virtual Museum of Natural History | Virtual War Museum