zo·e·a 
(zō-ēə)
(zō-ēə)n. pl. zo·e·ae (-ēē) or zo·e·as
A larval form of crabs and certain other decapod crustaceans, characterized by thoracic appendages used for swimming and often one or more spines on the carapace.
[New Latin, from Greek zōē, life; see AZO-.]
zo·eal adj.