Chapter 1, The Reptilian Spectacle - UWSpace - University of ...

1.6 Conclusion
As the reader can ascertain from this review, it is clear that although the reptilian spectacle has
intrigued researchers for over two centuries, many questions about it remain captivatingly unanswered.
What are the visual implications of its vasculature and of abrasions on its surface? How does the
spectacle achieve transparency and what compositional characteristics allow for a transparent spectacle
scale? What makes the snake spectacle scale more resilient than that of a gecko? What sensory
information is obtained from the spectacle innervation? What selective pressures are responsible for
the evolution of a spectacle or ensure the continued presence of spectacles in any species? What factors
in developmental genetics strongly decrease the likelihood of reversion to a lidded form as is thought
to have occurred in Eublepharidae?
The research presented in the next three chapters will provide some answers to questions of the
physiology of the spectacle vasculature, the spectacle scale’s spectral transmittance, and the spectacle
scale’s biochemical composition. Of course, the answers will in turn raise many more questions to be
addressed by future research.
1.7 Organization of the following chapters
The next three chapters present original research that is organized chronologically in the order in
which the experiments were conducted. The investigations cover three main characteristics of the
spectacle and its corneous scale: the physiology of its vasculature, the optical characteristics of the
scale, and the biochemical composition of the scale as follows:
• Chapter 2 describes investigations on the blood flow patterns in reptilian spectacles, effectively
adding the 4th dimension to the already well-described 3-dimensional anatomical structure of the
spectacle blood vessels.
31