The Protonephridial System of Temnocephala novaezealandiae: Structure of the Flame Cells and Main Vessels.

Abstract

The terminal organ of the protonephridial apparatus (flame cell) of Temnocephala novaezealandiae is a cyrtocyte with processes supported by a single cylinder of long, dense rods. The rods are microtubule aggregates. The processes are linked by extracellular filaments, and are continuous with radial extensions correlated with the formation of a fluid-filled extracellular space. The axial microtubules of the luminal flame cilia occupy parallel planes. The flame cell cilium is compared with the non-motile cilium of the epidermal sensory tufts. The main protonephridial vessels are composed of epithelial cells honeycombed by tubular infoldings of the basal plasmalemma associated with many mitochondria. The probable significance of the protonephridial apparatus in osmoregulation and ionic regulation is discussed. [AS]