Hate to say it, but Ganong, Genung, Ganoung, GaNun, etc. all come from one man named Jean Guenon (he couldn't spell it), and guenon is French for "baboon", particularly a group of arboreal species. Zoologists pronounce it 'Gwenon' . You can see them in any good zoo; National Geographic had a TV special on them some years ago also. There are still plenty of Frenchmen using the name. The name may be very old and might not always have referred to monkeys: some think it might have meant 'friendly' originally, but it was already associated with these little guenon monkeys by the middle ages when they were kept as pets.