What is the retracter bulbi muscle of a frog?

The retractor bulbi muscle in frogs is a specialized muscle that helps in retracting the eyeball into the socket. This action is particularly useful for frogs as it allows them to protect their eyes while feeding or during other activities. When the muscle contracts, it pulls the eye backward into the orbit, which can also help in moistening the eye surface with saliva. This adaptation is crucial for their survival, aiding in both feeding and defense against predators.