Complex sentence: The tricuspid valves of the heart are generally said to have derived their name from Erasistratus; but this appears to be an oversight, as Galen attributes it not to him, but to one of his followers.
Split into simpler sentences: The tricuspid valves of the heart are generally said to have derived their name from Erasistratus. This, however, appears to be an oversight, as Galen attributes it not to him, but to one of his followers.