metanauplius

from The Collaborative International Dictionary of English v.0.48

Metanauplius \Met`a*nau"pli*us\, n. [NL. See {Meta-}, and
   {Nauplius}.] (Zool.)
   A larval crustacean in a stage following the nauplius, and
   having about seven pairs of appendages.
   [1913 Webster]