What is the function of the bones in bats that are homologous to finger bones in humans?

The function of the bones in bats that are homologous to finger bones in humans is to FLY.

Explanation:

Homologous anatomy - it means that the organisms have the same anatomy or bone structure but it is used for different functions. They are evolved from a common ancestor.

human beings, bats and birds have the homologous forearms. They have the same types of bones present in their forearm but however each of them use it for different purposes. A human being uses to lift things, cook, type and other mundane things whereas a bat uses it's forearms as wings to fly.