Definitions
from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun Any of various marine arthropods of the order Xiphosurida, especially Limulus polyphemus of eastern North America, having a large rounded body and a stiff pointed tail.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun A type of
chelicerate arthropod , of the genus Limulus, resembling a crab.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun large marine arthropod of the Atlantic coast of North America having a domed carapace that is shaped like a horseshoe and a stiff pointed tail; a living fossil related to the wood louse
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artoparts commented on the word horseshoe crab
The Delaware Bay region is home to the largest population of the American horseshoe crab (Limulus polyphemus), found along the western shores of the Atlantic Ocean from Maine to the Yucatan. Another three species live in the coastal waters from Japan to Indonesia. Related to scorpions, ticks and land spiders, horseshoe crabs have their own classification (Class Merostomata). Each spring during the high tides of the new and full moons, thousands of horseshoe crabs descend on the Delaware Bay shoreline to spawn. Males, two-thirds the size of their mates, cluster along the water's edge as the females arrive. With glove-like claws on its first pair of legs, the male hangs on to the female's shell and is pulled up the beach to the high tide line. The female pauses every few feet to dig a hole and deposit as many as 20,000 green, birdshot-sized eggs. The male then fertilizes the eggs as he is pulled over the nest. After the spawning is complete, the crabs leave and the waves wash sand over the nest. Despite their size and intimidating appearance, horseshoe crabs are not dangerous. It's tail, while menacing, is not a weapon. Instead, the tail is used to plow the crab through the sand and muck, to act as a rudder, and to right the crab when it accidentally tips over. Their central mouth is surrounded by its legs and while harmless, it is advisable to handle a horseshoe crab with care since you could pinch your fingers between the two parts of its shell while holding it. Horseshoe crabs have 2 compound eyes on the top of their shells with a range of about 3 feet. The eyes are used for locating mates. Horseshoe crabs can swim upside down in the open ocean using their dozen legs and a flap hiding nearly 200 flattened gills to propel themselves. Horseshoe crabs feed mostly at night and burrow for worms and mollusks. Horseshoe crabs grow by molting and emerge 25 percent larger with each molt. After 16 molts (9-12 years) they will be fully grown adults. The medical profession uses an extract from the horseshoe crab's blue, copper-based blood called lysate to test the purity of medicines. Certain properties of the shell have also been used to speed blood clotting and to make absorbable sutures.
February 26, 2009