Crustaceans
Mostly marine, some freshwater (“insects of the seas”)
Only arthropods with two antennae; variable number of biramous legs; appendages on both cephalothorax and abdomen
Decapoda: shrimps, lobster, crabs; cephalothorax shielded by carapace; 5 pairs of legs on cephalothorax
Most abundant plankton: Copepoda (marine, freshwater) and Cladocera (water-flees; freshwater)
Sessile crustaceans: Cirripedia (barnacles)
Common to all: nauplius larva