Fine structure of the external nasal gland of two lizards (Podarcis sicula campestris and Chalcides chalcides)

In this study, we describe the ultrastructural features of the external nasal gland in two lizards: ruin lizard (Podarcis sicula campestris) and seps (Chalcides chalcides). Two secretory cell types, which differ interspecifically, have been found in the secretory endpieces of the glandular tubules in both species examined. An unusual morphological observation was the presence of paracrystalline structures in the secretory granules of the seromucous cells of the external nasal gland of the seps. These structures may be related to the packaging mechanism of glycoproteins or to their macromolecular structure. They may also reflect segregation of heterogeneous subcomponents within the same secretory granule. The striated cells are located in the distal segment of the glandular tubules, and have the typical ultrastructural features of the cells which in some species of reptiles, but not in these two lizards, are known to be capable of elaborating a hyperosmotic saline solution.