Morphology and histology of the reproductive system of Sagitta planctonis Steinhaus, 1896 (Chaetognatha)

The morphology and histology of the reproductive organs of Sagitta planctonis forma planctonis and of S. planctonis forma zetesios are described. No difference in number of oocytes was observed. The existence of a temporary oviduct is questionable. It may be possible that the so-called accessory fertilization cells are not actually participating in fertilization, but they may have a resorptive or secretory function.