The only comparable fact among other worms is the Laurer's canal or genitointestinal canal in the Trematoda.
This last tube is probably the homologue of Laurer's canal (Goto, 8).
It is the opening of Laurer's canal and is homologous not with that of the "vagina" just mentioned, but with a totally distinct structure - the "yolkreceptacle" - which in ectoparasitic forms discharges into the gut instead of to the exterior (see fig.
Tnis duct (Laurer's canal) is sometimes rudimentary and ends blindly beneath the skin.
In B it is also joined by a paired vagina (kk) and by the "vitello-intestinal duct" (Laurer's canal), f.
This structure is regarded as the homologue of a canal (Laurer's canal) which in the Heterocotylea opens into the (After Monticelli.
A canal (Laurer's canal) leads from the oviduct or yolk-duct to the dorsal surface.