Adjacent cells in lymphatic capillaries overlap each other loosely. what is the unique structural modification that increases their permeability?

These cells form a unique structural modification that increases their permeability that is known as the minivalves. 

Adjacent cells are associated with adherents intersections on their horizontal films. They are found just beneath tight intersections. Their capacity is to give shape and strain to cells and tissues and they are adding the site of cell-cell flagging.