The digital pads of the tree frog, Hyla cinerea. I. The epidermis

As the digital pad cells grow from the germinal epithelium, the desmosomes on the distal surface oF tile cells become aligned and form pegs filled with tonofilaments on the surface of the outer row of cells. The outer pad cells are separated from each other distally, thus the cell and the pegs form two sizes of protrusions in series on the pad surface which can fit into substratum/irregularities. A dense material, apparently derived from transforming bodies in the cells, coats the plasma membrane of the surface cells, presumably to strengthen them.