 The arms display in the first and fourth quarters the gyronny prominent in Campbell heraldry reversed for difference.Apparently the gynronnies where included by the Campbell Lord Lyon because the MacTavishes had been followers (not a sept) of the Campbells since their occupation of Argyll.The second and third quarters are similar to, but differenced from Thomson of that Ilk, apparently because Tavish translates to Thomas, and MacTavish bears the meaning of "Son of Tavis/Thomas".