A1L1L1A1N1T1O1I1S1
9 points
ALLANTOIS is validvalid
a saclike part of a conceptus which collects liquid waste from the embryo, as well as exchanges gases used by the embryo [n ALLANTOIDES]
a saclike fetal membrane developing into umbilical cord and forming part of the placenta, also ALLANTOID [n ALLANTOIDES or ALLANTOISES]