CHAPTER II

THE EVIDENCE OF THE ORGANS OF VISION

Different kinds of eye--Simple and compound retinas--Upright and inverted retinas--Median eyes--Median or pineal eyes of Ammocoetes and their optic ganglia--Comparison with other median eyes--Lateral eyes of vertebrates compared with lateral eyes of crustaceans-- Peculiarities of the lateral eye of the lamprey--Meaning of the optic diverticula--Evolution of vertebrate eyes--Summary 68