Аннотация:ON BIOLOGY AND ULTRASTRUCTURE OF BOTHRIOCEPHALUS SCORPII FROM INTESINE OF THREE-SPINED STICKLEBACKKolesnikov I.A., Biserova N.M.МГУ имени М.В. Ломоносова, Москва, Россияkolesivan96@gmail.comSummary. The ultrastructure of the tegument of Bothriocephalus scorpii plerocerci was described. Two types of secretory cells and two types of free endings were found. The larvae from the intestine possess a sparse glycocalyx and symbiotic bacteria among microtriches.Ключевые слова: tegument, secretory cells, tumulus, bacteria.