MORPHOGENESIS OF THE GENITAL DUCTS AND SPERMATHECAE CLITELLIO-ARENARIUS, HETEROCHAETA-COSTATA, TUBIFICOIDES-BENEDII (TUBIFICIDAE) AND STYLARIA-LACUSTRIS (NAIDIDAE) (ANNELIDA, OLIGOCHAETA)
Lm. Gustavsson et C. Erseus, MORPHOGENESIS OF THE GENITAL DUCTS AND SPERMATHECAE CLITELLIO-ARENARIUS, HETEROCHAETA-COSTATA, TUBIFICOIDES-BENEDII (TUBIFICIDAE) AND STYLARIA-LACUSTRIS (NAIDIDAE) (ANNELIDA, OLIGOCHAETA), Acta Zoologica, 78(1), 1997, pp. 9-31
The development of the male genital ducts in Clitellio arenarius, Tubi
ficoides benedii, Heterochaeta costata (Tubificidae) and Stylaria lacu
stris (Naididae) is studied with the purpose of investigating the homo
logies between different parts of the ducts. In both Tubificidae and N
aididae, the male duct comprises a funnel, a vas deferens and an atriu
m. There may also be a prostate gland (diffuse or compact) in associat
ion with the duct. The funnel and vas deferens, in all four species, o
riginate from the peritoneal (mesodermal) cells in the posterior septa
in the testes segment, whereas the atrium develops from an epidermal
(ectodermal) invagination. The prostate glands have different origins
in different taxa; in S. lacustris it differentiates from the peritone
al (mesodermal) cells surrounding the atrium, but in H. costata and T.
benedii it develops by a multiplication of the atrial (ectodermal) ce
lls; C. arenarius lacks a prostate gland. The development of the sperm
athecae and the female duct is also studied. The spermatheca is an epi
dermal invagination. The female duct is of mesodermal origin. However,
the position of the duct differs; in S. lacustris the female duct is
lateral and the pore is in the ovarian segment, while in the tubificid
s studied the duct is ventral with the pore in the segment behind the
one containing the ovary. (C) 1997 The Royal Swedish Academy of Scienc
es.