Fig. 1.

Cross-section of the retina for three salamander species. From top to bottom in each cross-section: outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Thin lines indicate the borders between layers. Mudpuppy, tiger salamander, and axolotl retinas are structurally alike with large cells and thin plexiform layers. Mudpuppy and tiger salamander retina cross-sections are autoradiographic and adapted respectively from [203], Copyright (1984) and [204], Copyright (1997) with permission from Elsevier. Axolotl retina cross-section from light microscopy adapted from [50] with permission (John Wiley and Sons, Copyright 1973 The Wistar Institute of Anatomy and Biology).