Limiting median lines frequently determine the yolk

In two-dimensional Euclidean spatial voting models the yolk is the smallest circle which intersects all median lines. It has been assumed that limiting median lines, which intersect two voter ideal points, are sufficient to determine the yolk but recently counter examples have been reported. This note describes the impact of those findings on the results of computation of the location and size of yolk.I wish to acknowledge a number of helpful conversations with Craig Tovey and Nicholas Miller. Any errors which remain are my own.