Source : Webster's Revised Unabridged Dictionary (1913)

Nauplius \Nau"pli*us\, n.; pl. {Nauplii}. [L., a kind of
   shellfish, fr. Gr. ? ship + ? to sail.] (Zo["o]l.)
   A crustacean larva having three pairs of locomotive organs
   (corresponding to the antennules, antenn[ae], and mandibles),
   a median eye, and little or no segmentation of the body.

Source : WordNet®

nauplii
     See {nauplius}