Definition of horseshoe crab
: any of several closely related marine arthropods (order Xiphosura and class Merostomata) with a broad crescentic cephalothorax, six pairs of legs, and a spikelike tail especially : one (Limulus polyphemus) of coastal waters from Maine to the Yucatán Peninsula
Note: The horseshoe crab is often said to have five pairs of legs since the first pair is greatly reduced in size and used mainly for feeding. All the legs of the horseshoe crab end in claws except for the last pair of legs which have leaflike expansions used mainly for pushing.
… a horseshoe crab … is a Swiss army knife of jointed limbs—for walking, swimming, grasping, shredding, and defending. — Carl Zimmer … the horseshoe crab has changed little since an ancestor was fossilized 150 million years ago … — National Geographic— called also king crab
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Time Traveler for horseshoe crab
The first known use of horseshoe crab was in 1797
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