In the bovine. The fetal and caruncular villi gradually become more branched and complex which greatly enhances their interdigitation. The epithelium covering the bases of the fetal villi is __1__, while that covering the tips is __2__; both cell types have microvilli. The microvilli of the __2__ cells interdigitate with microvilli in the depths of the caruncular crypts (i.e. on the bases of the caruncular villi). However, the cells covering the tips of the caruncular villi do not have microvilli (the microvilli of the __1__ cells therefore cannot interdigitate).