THE GENUS POLYARTHRA IN LAKE PEIPSI

In Lake Peipsi (Estonia) Polyarthra species often dominate the rotifer community, and are represented by 6 species: Polyarthra dolichoptera Idelson, P. longiremis Carlin, P. luminosa Kutikova, P. major Burckhar dt, P. remata Skorikov, P. vulgaris Carlin. The highest diversity occu rs in August-September, with P. remata and P. luminosa most abundant. Morphometric data including measurements of body, fins and various typ es of eggs are given. The seasonal development of the different specie s and their life cycles are considered.