Reptiles possess a nervous system divided into distinct parts, including the brain and sensory structures like eyes, olfactory organs, and auditory systems. Their cerebral hemispheres are specialized for smell while their optic lobes process visual information; chameleons have swiveling eyes that can form independent images to enhance depth perception during predation. Snakes' fused eyelids create a spectacle membrane aiding vision protection, with elliptical lenses adapting focus on nearby objects through ciliary muscle action. Additionally, reptiles exhibit unique defensive adaptations such as blood sinuses at the base of nictitating membranes filled with blood for protective behavior.