Early Development of the Adrenal Glands in the Grass Snake Natrix natrix L. (Lepidosauria, Serpentes)

1 Introduction.- 1.1 Comparative Morphology of Vertebrate Adrenals.- 1.2 History of Reptile Adrenal Studies.- 1.3 Nomenclature of Reptile Adrenal Glands.- 1.4 Adrenal Glands in Reptiles.- 1.5 Embryonic Development of Reptile Adrenals.- 1.6 Why Do We Study the Development and Differentiation of Adrenal Glands in Snakes?.- 2 Materials and Methods.- 2.1 Materials-Characteristic Features.- 2.2 Normal Developmental Table.- 2.3 Methods of Research.- 3 Results.- 3.1 Microscopic Anatomy of the Interrenal Tissue Primordium.- 3.2 Ultrastructure of the Interrenal Tissue Primordium.- 3.3 Microscopic Anatomy of the Chromaffin Tissue Primordium.- 3.4 Ultrastructure of the Chromaffin Tissue Primordium.- 3.5 Stages of Adrenal Development.- 4 Discussion.- 5 Conclusions.- 6 Summary.- References.