An extra-embryonic membranous sac derived from the YOLK SAC of REPTILES; BIRDS; and MAMMALS. It lies between two other extra-embryonic membranes, the AMNION and the CHORION. The allantois serves to store urinary wastes and mediate exchange of gas and nutrients for the developing embryo.
Synonyms: Allantois, Membrane, Allantoic, Allantoic Membrane
Instance information
comment
91(75); was see under FETAL MEMBRANES 1975-90 ,search FETAL MEMBRANES 1966-74 ,91; was see under FETAL MEMBRANES 1975-90
identifier
D000482