[Neuroendocrine control of reproduction in molluscs].

Experiments carried out, in vitro and in vivo on gastropods and lamellibranchs have shown the existence of gonadic factors of differenciation and working. In hermaphrodites or gonochoric molluscs, the primary germ cells self differentiate into oogonia and oocytes, the differenciation and maintenance of male cells depending upon factors secreted by the cephalic ganglia. Neurosecretory cells seem to exert a control upon mitosis of germ cells, meiosis, vitellogenesis (cerebral ganglia) or spawning (visceral ganglia). Some organs present in gastropods (dorsal bodies, optic tentacle) could act to modulate these actions.