Complex sentence: This is the thickest part, and overlaps the tela chorioidea of the third ventricle and the mid-brain, and ends in a thick, convex, free border.
Split into simpler sentences: This is the thickest part, and overlaps the tela chorioidea of the third ventricle. It overlaps the tela chorioidea of the third ventricle and the mid-brain, and ends in a thick, convex, free border.