The zoea (from ; pl. zoeae, zoeas)'s a free-swimming larval stage of crustaceans. It follows the nauplius stage and precedes the post-larva. Zoea larvae swim with their thoracic appendages, as opposed to nauplii, which use cephalic appendages, and megalopa, which use abdominal appendages for swimming. The zoea often has spikes on its carapace, which may assist these small organisms in maintaining directional swimming. These spikes also play a role in the improvement of buoyancy and anti-predat… (More on Zoea)