Objective To investigate the telencephalon developmental characteristics of Hynobius leehii, and enrich the research data of comparable neurobiology and nervous system development of amphibian. Methods HE staining and Nissl staining methods were used to study the telencephalon histological structure of Hynobius leechii at both the metamorphosis and the adult phases, and to explore the developmental phases of telencephalon. Results The olfactory bulb could be roughly divided into 6 layers from lateral to medial. The lateral cerebral ventricles at the metamorphosis phase were smaller than those at the adult phase, and there were no clear borderlines between the primordial pallium and the primordial hippocampus, or between the primordial pallium and the primordial piriform area. Moreover, the cells in the primordial piriform area were more closely distributed than those in the primordial hippocampus or the primordial pallium. Compared with those at the adult phase, cells in nucleuses at the metamorphosis phase were larger in number and more closely distributed. Conclusion The telencephalon of Hvnobius leehii at the metamorphosis phase has generally formed the adult structure, however, it is still at a transition state of differentiation to maturity during the development of Hynobius leehii.
