Freeze fracture replicas of zonula occludens junctions from the large intestine of a tadpole (upper) and intestine of a post-metamorphic toad (lower). The occluding junction appears as a meshwork of ridges on the P-face or a corresponding pattern of grooves on the E-face. Images originally published in Hull and Staehelin, J. Cell Biol. 68:688-704, 1976 and reprinted with permission as Figures 62 (upper) and 63 (lower) from Chapter 3 (Junctional Specializations) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. A PDF copy of the accompanying chapter is available on the ASCB's BioEDUCATE website.