An account is given of swimming and feeding in the nauplii of Artemia, Balanus, Calanus and Oithona, with observations on other nauplii. Previous work is reviewed.
In all cases the antennae are the principal locomotion organs. The antennules may play little or no part in locomotion and are mainly balancing organs.
In Artemia the antennae are also the chief food collecting organs. Particles are swept into the oral region by the antennal setae and then carried to the mouth by spines on the reduced mandibles.
In Balanus and most planktonic copepods, the principal food collecting appendage is the mandible; particles are swept into the oral region by its long ventral setae and passed to the mouth by spines like those of Artemia.
The nauplii of Penaeidea and Euphausiacea and of Euchaeta (Calanoida) do not feed.