noun. A thin, tough, membranous sac that encloses the embryo or fetus of a mammal, bird, or reptile. It is filled with a serous fluid in which the embryo or fetus is suspended.

noun. In echinoderms, the sac in the pluteus larva inclosing the developing echinus.

noun. In anatomy and vertebrate zoöl., one of the fetal appendages; the innermost one of the membranes which envelop the embryo of the higher vertebrates, as mammals, birds, and reptiles; the lining membrane of a shut sac, familiarly called the “bag of waters,” in which the fetus is contained.

noun. In entomology, a membrane which surrounds the larva of many insects, as the millepeds (Iulidæ), for some time after they are batched from the egg. It is regarded by some as the analogue of the amnion of a vertebrate.

noun. A reflected portion of a membrane, in ascidians, which lines the inner wall of the ovisac, and forms a kind of amniotic investment of the embryo.

noun. In botany, a name formerly given to the fluid contents of the embryo sac.

noun. Sometimes erroneously written amnios.

noun. A thin membrane surrounding the embryos of mammals, birds, and reptiles.

noun. the innermost membrane of the fetal membranes of reptiles, birds, and mammals; the sac in which the embryo is suspended.

noun. thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)

"In these three classes alone we find the remarkable embryonic membrane, already mentioned, which we called the amnion; a cenogenetic adaptation that we may regard as a result of the sinking of the growing embryo into the yelk-sac."

false amnion  true amnion  

amniocentesis  amnionic  amniotic  

sac  

afterbirth  baaing  chorioallantoic  cotton/polyester  nanowire  

allantoic membrane  amniotic sac  arachnoid membrane  basement membrane  conjuctiva  

amnia