Fig. 38. Eyelid closure. A. At 6 weeks' gestation in the human, lid folds are apparent (arrows). Note the relationship to the lateral nasal prominence (LNP), maxillary prominence (Mx), external ear (E), and forelimb (F) (× 40). B. At 8 weeks' gestation, the facial prominences have fused and the eyelids are beginning to close (× 20). C. At 9 weeks' gestation, the eyelids begin to fuse (× 300). D. Light micrograph illustrating the marginal epithelium (M) undergoing simultaneous proliferation and cell death in preparation for lid fusion (× 929). E and F. At 10 weeks' gestation, fusion is complete, and the epithelial proliferation associated with formation of the seam can be seen (E, × 58; F, × 280). (A-C, E, and F, courtesy of Kathy Sulik.)