part_of part of part of has developmental contribution from has developmental contribution from cloaca embryonic cloaca cloaca endoderm-lined chamber that develops as pouch-like dilation of the caudal end of the hindgut and receives the allantois ventrally and two mesonephric ducts laterally; caudally it ends blindly at the cloacal membrane formed by the union of proctodeal (anal pit) ectoderm and cloacal endoderm, with no intervening mesoderm[MP]. EHDAA2:0000256 this class represents the embryonic form of the cloaca, as found in both mammals and non-mammals. UBERON:0000163 uberon EMAPA:27573 Wikipedia:Cloaca_(embryology) Endoderm-lined chamber that develops as pouch-like dilation of the caudal end of the hindgut and receives the allantois ventrally and two mesonephric ducts laterally; caudally it ends blindly at the cloacal membrane formed by the union of proctodeal (anal pit) ectoderm and cloacal endoderm, with no intervening mesoderm[MP]. EHDAA:4895 embryo renal system intermediate mesoderm internal anal region