Fig. 6. Eyelid fusion in the mouse. (A) A scanning electron micrograph of the mouse eye at E15, when eyelids are just beginning to advance forwards over the corneal epithelium. (B) A transverse section through the eye taken at the level indicated by the broken line in A. (C) Transmission electron microscopy of the leading edge cells (corresponding to box in B) shows expression of numerous filopodia. (D) When the two eyelids confront one another at the anterior and posterior canthi, the filopodia of opposing epithelial cells interdigitate, just as during Drosophila dorsal closure.