Crustacean larva stop after a single copepodid stage. Once the gonads develop, there are no further moults. Chalimus (plural chalimi) is a stage of development of a copepod parasite of fish, such as the salmon louse ("Lepeophtheirus salmonis"). "Chalimus" Burmeister, 1834 is also a synonym for "Lepeophtheirus" Nordmann, 1832. The single genus in the Facetotecta, "Hansenocaris", is only known from its larvae. They were first described by Christian Andreas Victor Hensen in 1887, and named "y-nauplia" by Hans Jacob Hansen, assuming them to be the larvae of barnacles. The adults are presumed to be parasites of other animals. Crustacean larva Crustaceans may
Polyphemus (crustacean) pairs of legs with exopodites, or outer branches. The legs are adapted for catching mobile prey, generally smaller species of water flea such as young "Daphnia" and "Bosmina". "Polyphemus" has two compound eyes that are fused to form a single unit, with a zoned set of receptors. This zoned structure is paired with an eye-control system that allows the "Polyphemus" to visually distinguish target size to avoid predators and track prey. "P. pediculus" is approximately in length. "P. exiguus", while similar in morphology, is smaller. Polyphemus (crustacean) Polyphemus is a genus of water fleas, and the only genus in the