Lighter, I'm doing this from memory ("shielding" far from home), but the ?Graves song beginning "A wan cloud was drawn o'er the dim, weeping dawn....", as recorded by John McCormack, is set to an air which I'm pretty sure I've also seen as "The Little Red Lark", with another set of words in an old song-book. Might be in error, or it might be a worthwhile line to pursue.
By "extra measure" I wonder do you mean the way each fourth line has the last three syllables all on the same, repeated pitch? Good Luck.