Faldage, if you and max are trying to make the point that the Zildian marsupial is a possum and the American one is a 'possum, I have to cry Nitpicking! I don't believe I've ever heard anyone use the full form, opossum, except in a technical context and I don't think you find it with an apostrophe in the dictionary. Are you going to tell us that the plural of possum is possa?