Joe, sorry to take so long to get back with you, but I've been traveling again and I'm only now catching back up with Gotmead messages. If the stuff on top looks like organized colonies of bacteria or mold rather than just floating yeast crud, then I'd recommend racking the clear mead out from under the colonies (as I noted earlier), then dose the mead with potassium metabisulfite to prevent the reappearance of the infection. While you have it in the process of racking, you should draw off a sample for tasting/smelling and measurement of SG if you have a hydrometer. It is important to know what the final SG is, or if you don't have any way of measuring the SG, at least taste to see if it has fermented out enough for your taste. If at all possible, keep the liquid level topped up near the narrow neck of the carboy to minimize the potential for oxidation, and seal it up with a stopper and airlock. Let the sulphited mead rest for a couple of weeks and take a look at it periodically over that time to see if there are no more obvious signs of infection.
Since you've got what is likely an infection in there, I'd recommend being generous with the sulphite addition - go with 1/2 gram per gallon (or since Campden tablets are 0.44 grams apiece, I'd use 6 tablets in a full 5 gallon carboy). That will provide a substantial free sulphite level, one that in a traditional mead should knock out all typical infection agents, including all wild yeasts. Since your mead is a traditional, the free sulphite won't find much to bind with in there, but over the course of a few weeks most of it will come out of solution and dissipate in the airspace at the top of your carboy, displacing the air that is there to begin with.
Good luck with this one, and keep us apprised of how it goes from hereon out.