Final answer:
The protective eyelids of a shark that cover the eyes during feeding are known as the nictitating membrane, serving as an extra layer of protection.
Step-by-step explanation:
The eyelids that cover and protect the eyes on a shark when they bite prey are called the nictitating membrane. Similar to the way a third eyelid protects the eyes of crocodiles underwater, the nictitating membrane in sharks serves as an extra layer of protection during feeding to prevent injury to the eyes. This adaptation is important for sharks' predatory lifestyle as it ensures their vision, a critical sense for hunting, is safeguarded.