Actually, thing, the melody goes like this:

Row, row, row your boat, gently down the stream
1 1 1 2 3 3 2 3 4 5
merrily, merrily, merrily, merrily, life is but a dream
888' 555 333 111 5 4 3 2 1

I am using the 1-8 notation, instead of a specific key or solfege syllables, because it seems more intuitive this way. It could also be written as:

do-do-do-re-mi-mi-re-mi-fa-so
do-do-do-so-so-so-mi-mi-mi-do-do-do / so-fa-mi-re-do