Any of several crabs, especially the European or Caribbean hermit crabs (Pagurus bernhardus and Coenobita clypeatus)(noun)
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Use "soldier crab" in a sentence
"Among other stalked-eyed crustaceans is that with one red, shielding claw, absurdly large, and which scuttles among the roots, making a defiant clicking noise — the fiddle or soldier crab (GELASIMUS"