ALLANTOIS

(Lat.), n. f. A?l(a1)-la?n(la®n)‘to-i2s. Gen., all an to'idis, From dAAis, a sausage, and eléos, likene . Gr, dAAav- ToerBÿs, bunv (xeTèv) ddAavroedys. Lat., allantoides, tunieu farci min a lis (seu farci malis), membrana farci minos a. Fr, all an toïde. Ger., All an toïs, Harnsack, Wursthäutchen. It, all an to ide. Sp., alantéides. The urinary vesicle of the embryo; a flask-like diverticulum, connected with the intestine by a narrow pedicle, situated in the space between the umbilical vesicle, the amnion, and the subzonal membrane. It is found only in the Amniota (all an to idea), A dilatation of its pedicle ultimately forms the urinary bladder, and its vascular portion gives rise to the umbilical cord and the foetal elements of the placenta, [A. Thomson (A, 5): A, 11.) See figure under Feetal envetorrs.—A’flii igkeit (Ger.), See ALLANTOIC Jjivid.—A’hicken (Ger.). Ga er’s term for a thickening of the anterior wall of the a. which appears in the chicken-emhryo in the latter part of the third day —A’hôlhle (Ger.). See Sac of the a.—. See Pedicle of the a— (Ger,), A thickened bulging ‚po ion of the viscera] mesoblast, being a thick ma of cells at the posterior extremity of the eı, which is the first rudiment of the allantois and contains a small diverticulum coming from the rectum, which is the he ginning of the cavity of the allantois. [H.]—Diverticulum allantoid is. See under Diverticv- LUM.—Sac of the a. Ger., All an to ishôhle, That portion of the original a. which remains outside the abdominal wall after the urinary bladder has been formed from another port i of i.—Vas: layer of the a, The mesoblastic or outer layer of the a., which lines the interior of the chorion, [A. Thomson (A, 5).]