optic lobe n.
Either of two lobes of the dorsal mesencephalon, containing primary visual centers.
Of these, it will be observed, the optic lobe is the largest in the brain of the fish (Fig. 45).
Spurzheim gives a view of the brain of the pike with an optic lobe partially opened, to show the ventricle.
In the Dipnoans the cerebral hemispheres are united, while the optic lobe and cerebellum are very small.