Annotations of the two versions of Leonardo's The Virgin Of The Rocks, Louvre & National Gallery London, prominent in the current National Gallery Exhibition, "Leonardo da Vinci, the Milan years", refer to an inscription "Ecce Agnus Dei" appearing on the 'scroll' of John the Baptist, the infant on the left of the painting, in the later {London} version.

I have studied several reproductions of the painting, and cannot locate this scroll, or its inscription.

Can anyone find it and direct my eye as to where to look, please?

~Michael~