 For the professional student I may observe that I have relied on the authority of de Goeje in adhering to my own original opinion that the word Mukaukas is not to be regarded as a name but as a title, since the Arab writers to which I have made reference apply it to the responsible representatives of the Byzantine Emperor in antagonism to the Moslem power.  I was unfortunately unable to make further use of Karabacek's researches as to the Mukaukas.