The vertebrate eye has been, and continues to be, an object of interest
and of inquiry for biologists, physicists, chemists, psychologists, and
others. Quite apart from its important role in the development of
ophthalmology and related medical disciplines, the vertebrate eye is an
exemplar of the ingenuity of living systems in adapting to the diverse
and changing environments in which vertebrates have evolved. The wonder
is not so much that the visual system, like other body systems, has been
able to adapt in this way, but rather that these adaptations have taken
such a variety of forms. In a previous volume in this series (VII/I)
Eakin expressed admiration for the diversity of invertebrate
photoreceptors. A comparable situation exists for the vertebrate eye as
a whole and one object of this volume is to present to the reader the
nature of this diversity. One result of this diversification of ocular
structures and properties is that the experimental biologist has
available a number of systems for study that are unique or especially
favorable for the investigation of particular questions in visual
science or neurobiology. This volume includes some examples of progress
made by the use of such specially selected vertebrate systems. It is our
hope that this comparative approach will continue to reveal new and
useful preparations for the examination of important questions.