The morphology of the female reproductive structures of Penonyx excavatus (Oligochaeta)

Perionyx excavatus (Oligochaeta) is a vermicomposting earthworm of which li ttle is known regarding its reproductive strategies. This is a second paper by the authors on the morphology of the reproductive structures in an atte mpt to reconcile the scanty and confusing literature on this topic and to i nvestigate the possibility of self-fertilization. The investigation was don e by examining the gross anatomy and histology, using scanning and transmis sion electron microscopy. The female reproductive system consists of three pairs of spermathecae in segments seven, eight and nine. Each spermatheca c onsists of one ampulla and four sessile diverticula. The spermathecae open separately but midventral by in the intersegmental groove anterior to the s egments in which they occur. One pair of ovaries is found in segment 13. Th e ova are released into the body cavity and are collected by the two ciliat ed ovum funnels, also in segment 13. The two short oviducts leading from th e ovaries, join into a common oviduct. The common oviduct opens into the fe male opening, which is situated midventrally, anterior to the ring of body chaetae on segment 14.