I am certain that it is an "a." You are right that the "m" before the "a" cannot be made out clearly (due to the dark background) but the character that comes before the "h" is certainly an "a" and looks exactly like every other "a" in his signature. Actually if you look carefully after "Para" you will see against the dark backround two pointed peaks after which follows the alleged "a." If you look at his signature in the picture of Paramahansaji below the picture Lahiri Baba (on the same page) you will see that the "m" is again signed with two pointed peaks. The "a" that I am speaking of is clearly rounded on the top and therefore could not possibly be part of an "m" because his m's consist of pointed peaks and not rounded mounds. Actually, if I didn't know his name and was reading this then I might misread it as "Parasahansa" because the first pointed peak of the "m" is obscured by the dark background and the second peak of the "m" looks a little like an "s" because of the way Master made his m's. But there is no way that I would read it "Paramhansa." The "a" is just like all the a's he makes...the only uncertainty is in the "m."