The chorionic villi are initially accommodated in corresponding depressions in the caruncle. However, as the villi grow and branch, the depressions deepen to form __1__ (the caruncular tissue between the deepening __1__ now constitutes maternal or caruncular villi). Simultaneously, the caruncle becomes enlarged and more vascular. The caruncles in the pregnant horn enlarge tremendously; the largest measure _3_ cm in the bovine, and _4_ cm in the sheep. The caruncles in the non-pregnant horn also enlarge, but to a lesser extent.