Role of the nephridia in the elimination of foreign cells from the coelomic fluid of two polychaete annelids, with observations on the structure of the nephridia.
Formalinized sheep red blood cells and living bacteria (Serratia marinorubra) are rapidly phagocytosed. When infected into Arenicola marina and Neoamphitrite figulus. Phagocytes clump but later disperse. After sheep red cells have been taken up by phagocytes they migrate through the nephridial cells into the lumen. After bacteria have been taken up by the phagocytes they also clump and again later disperse but they are not found within the nephridial cell walls probably because the bacteria are effectively eliminated by the phagocytes. Formalinized red cells are probably indigestible and such particles can only be eliminated by active migration of the phagocytes to the exterior, or are sequestered or, more rarely, encapsulated. Loss of either red cells or bacteria directly through the nephridia is no more than can be accounted for by normal urine flow.
Dales
R P
RP
Department of Zoology, Royal Holloway and Bedford New College (University of London), Egham Hill, Surrey, England.
Cummings
M O
MO