Life Cycle: "Adult worms attach to the intestinal walls of waterfowl. The eggs are passed in the feces and the larval stage develops in the isopod or crustacean intermediate hosts. The definitive host is infected upon eating intermediate hosts" (Parasite Species).
Main longitudinal lacunar canals lateral; tegumental nuclei fragmented, numerous, occasionally restricted to anterior half of trunk; nuclei of lemnisci and cement glands fragmented; spines present on trunk of some species; single ligament sac of female not presistant throughout like; protonephridia absent; cement glands separate, tubular to spheroid; eggs oval to elongated, sometimes with polar thickenings of second membrane… Proboscis spheroid to cylindrical, armed with numerous hooks in alternating longitudinal rows; proboscis receptacle double walled, with brain near center; parasites of reptiles, birds, and mammals.
Sources: Roberts, L.S. and Janovy Jr., J. 2009. Foundations of Parasitology, p. 508.
Parasite Species summary page: Filicollis anatis.