Electron microscopy of the dorsomedial cortex in the lizard Psammodromus algirus

The cellular populations and the plexiform layers of the dorsomedial cortex of Psammodromus algirus are described at the ultrastructural level. Solitary globous cells are located in the outermost layer of the cortex, the superficial plexiform layer. Double pyramidal cells of the cellular layer show uniform ultrastructural characteristics. Displaced double pyramidal cells, vertical fusiform cells, and globous cells are found in the deep plexiform layer. Two types of dendritic spines are described. Large spines may contain membranous sacs and mitchondira and are located at the upper third of the superifical plexiform layer; small spines do not contain organelles and are located throughout the entire cortex. Two types of axon terminals are widely distributed in both plexiform layers: terminals with only clear vesicles and terminals with both dense-core and clear vesicles. Terminals with large dense-core vesicles may be related to peptidergic synapses and are more frequent at the upper levels of the superficial plexiform layer. The neuroglia described in the dorsomedial cortex of Psammodromus are protoplasmatic astrocytes and oligodendrocytes.