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allantois

(ə lan′tō is)

a membranous pouch with a rich blood supply in the embryos of birds, reptiles, and mammals: it is an organ of respiration and excretion for embryonic birds and reptiles: in mammals it helps form the placenta

Origin: ModL < Gr allantoeidēs, sausage-shaped < allas, sausage (prob. < dial. allē, garlic, via Oscan *allo < L alium, allium) + -eidēs, -oid

See allantois in American Heritage Dictionary 4

noun pl. al·lan·to·i·des (ălˌən-tōˈĭ-dēzˌ)

A membranous sac that develops from the posterior part of the alimentary canal in the embryos of mammals, birds, and reptiles. It is important in the formation of the umbilical cord and placenta in mammals. Also called allantoid.

Origin:

Origin: New Latin

Origin: , from allantoīdes

Origin: , from Greek allantoeidēs, sausage-shaped

Origin: : allas, allant-, sausage

Origin: + -oeidēs, -oid

Related Forms: