Chiron (hypothetical moon)
Hermann Goldschmidt announced the discovery of the ninth moon of Saturn in April 1861, which, he said, orbited between Titan and Hyperion. Goldschmidt's discovery was never confirmed, and Chiron was never seen again.
In 1898, William Henry Pickering discovered Phoebe, which is now considered the ninth moon of Saturn. Strangely, in 1905, Pickering believed that he had discovered another moon of Saturn, which, he reported, orbited the planet between Titan and Hyperion. He called this new moon Themis. Themis, like Chiron, was never sighted again.