A Histological Study of the Optic Lobe in Takydromus septentrionalis

The histological structure of optic lobe in Takydromus septentrionalis was studied. The optic lobe could be divided into two parts: dorsal tectum and ventral tegmentum, but there was no distinct boundary between them. The white matter and the gray substance distributed alternatively. From lateral to medial, tectum consisted of 8 layers: molecular layer, outer gray layer, superficial white layer, middle gray layer, middle white layer, deep gray layer, deep white layer, and ependymal layer. The cell layers in tegmentum were indistinct. The left and right optic lobes were linked by the transversal fibers at the anterior part. The left and right optic lobes communicated with aqueduct of sylvius and vertical culcus at the mid-posterior part. The mesencephalon of T. septentrionalis was compared with other lower vertebrate animals. We speculate that T. septentrionalis lies at lower status in evolution.