The female reproductive system in nematode systematics

Additional information is given on the female genital system in some Tylenchida and Araeolaimida. A comparison between these results and results formerly published on the orders Rhabditida, Dorylaimida and Enoplida revealed the difficulty of homologizing the several gonoduct parts found in these groups. The most important systematic character seems to be the number of cell rows in the oviduct : the orders Dorylaimida and Enoplida have one row, the orders of the Secernentea (Rhabditida, Tylenchida, ...) two rows and at least some Araeolaimida and Chromadorida three rows. Th e ovarian cap cell has only been found in the Secernentea, not in the Dorylaimida and Enoplida. Information is given on the subdivisions of the ovary, the function of the sphincters, the presence of a spermatheca and other uterus differentiations. Cell-constancy is stressed and the usefulness of the female reproductive system for the systematics and for the evolution is discussed