Noun
A genus of small schizopod shrimps found both in fresh and salt water; the opossum shrimps. One species inhabits the Great Lakes of North America, and is largely eaten by the whitefish. The marine species form part of the food of right whales.
Source: Webster's dictionaryBy the mysis stages, the pereiopods (thoracic appendages) start to be used instead of the antennae for locomotion. Source: Internet
By the last mysis stage, the beginnings of pleopods have appeared on the first five segments of the abdomen. Source: Internet