Sa. Reinecke et R. Pieters, THE MORPHOLOGY OF THE MALE REPRODUCTIVE STRUCTURES OF PERIONYX EXCAVATUS (OLIGOCHAETA), South African journal of zoology, 32(3), 1997, pp. 64-71
Perionyx excavatus (Oligochaeta) is a vermicomposting earthworm of whi
ch the reproductive strategies are little known. In order to obtain mo
re information on this, its reproductive systems were studied. Existin
g literature on the topic is either contradictory or scant. The invest
igation was done by examining the gross anatomy and histology, using s
canning and transmission electron microscopy. The male reproductive sy
stem consists of two pairs of testes in segments 10 and 11 and two pai
rs of seminal vesicles in segments 11 and 12. In mature worms the deve
loping spermatozoa are released by the testis into the body cavities o
f segments 10 and 11. The seminal vesicles in a particular segment rec
eive developing spermatozoa from the lumen of the preceding segment. T
wo pairs of ciliated sperm funnels also occur in segments 10 and 11 an
d become the ciliated vasa deferentia carrying the sperm. The vasa def
erentia on each side fuse to form only one vas deferens. These vasa de
ferentia reach the pair of prostatic glands in segment 18, each joinin
g the prostatic duct and opening via the ventral male openings adjacen
t to each other on segment 18. Associated with the male openings are r
etractable penial chaetae. The cellular composition and organelle dist
ribution of some organs and structures are also described. The positio
ns of the female reproductive structures are illustrated diagrammatica
lly in this paper.