allantoid, a. [Gr. shaped like a sausage; sausage + e'i^dos form.].
Of or pertaining to the allantois. [1913 Webster]
allantoid, n.
A membranous appendage of the embryos of mammals, birds, and reptiles, -- in mammals serving to connect the fetus with the parent; the urinary vesicle. [1913 Webster]