the comment about eggs sent me to google for a bit more info here is an
interesting summary for anyone intrested:

"Reproduction in Earthworms

Oligochaetes are hermaphrodites, with separate testis and ovaries. The
sexual organs, and the ducts that to and from them are situated in the
anterior (front) part of the animal, normally between segments 7 and 15. The
actual placement of the reproductive organs, including the openings of the
ducts, which are nnormallyaly on the same segments are important in
classification. In Lumbricuscus terrestris, a common worm in Western Europe,
the testis are in segments 10 and 11, the seminal vesicles in segments 9,11,
and 12, while the vas deferens opens on segment 15. The ovaries are found in
segments 13 and the oviduct opens on segment 14. The sexual organs and their
ducts are paired, one on each side of the worms body. Sperm travels from the
opening of the vas deferens to the clitellum, segments 32-36, along two
seminal grooves.

Copulation occurs on warm damp nights. the worms lie had to tail and side by
side. In this way the clitellum segments of each animal are opposite the
segments containing the sexual organs of the other. The clitella secrete a
mucous tube that surrounds the worm from before the first reproductive
segment to the clitella segments (segments 8 to 36 in L. terrestris). Sperm
received from the partner worm is stored in the spermathecal openings
(segment 9 in L. terrestris) and then the two worms separate.

Each worm now secretes a new mucous tube, one that is enriched with albumin
from the clitellum and wrapped in membranene. The eggs (5 - 16 in L.
terrestris) are shed into this tube along with some sperm. the worm then
backs out of the tube which now becomes an egg cocoon. Fertilisation occurs
inside the cocoon. The cocoon is left under the ground, or attached to
plants under the water and often changes shape, becoming darker, smaller and
harder. In L. terrestris only one egg survives the juvenile stage to emerge
from the cocoon, but in other species more than one will survive. The exact
detail vary from species to species but the general pattern remains the
same. "


taken from: http://www.earthlife.net/inverts/oligochaeta.html