The Mermaid is #289 in the Child cannon. Child (1882-1898)CPB
(vol V,
p151) references Motherwell's text above variant #289E. However, he
also (and primarily) references Motherwell's MS.MS-MOT, and I
presume that the words for #289E come mainly from that, as there are
quite a few differences between the two versions.
Motherwell gives just one verse for this version. He doesn't provide
a source. However, he does impart that the single verse in question
also occurs in some sets of Sir
Patric Spens.
As with all Motherwell's airs, I have added the verse text to the
score. In this case, the conjoining of the words with the tune may not
be ideal!