Redescription of, and comments on, Caligus lacustris Steenstrup et Lütken, 1861 (Copepoda, Caligidae), a parasite of freshwater fishes.

Caligus lacustris is the only freshwater species of a marine genus containing some 200 species. Although it is widespread and abundant in extensive freshwater habitats of the Old World, it has never been adequately described and accurately illustrated. This paper provides detailed description and illustrations of C. lacustris, based on new material from the territory of the USSR.