[W/K] :: horseshoe crab

  Limulus \Lim"u*lus\ (l[i^]m"[-u]*l[u^]s), n.; pl. Limuli
     (-l[imac]). [L., dim. of limus sidelong, askance.] (Zool.)
     The only existing genus of Merostomata. It includes only a
     few species from the East Indies, and one ({Limulus
     polyphemus) from the Atlantic coast of North America. Called
     also Molucca crab, king crab, horseshoe crab, and
     horsefoot.
     [1913 Webster]

  horseshoe crab
       n : 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 [syn: king crab, Limulus
           polyphemus, Xiphosurus polyphemus]