Mallory

The manifests were written at the port of departure from a document that an ancestor presented to the shipping clerk.
Of course small spelling or transcribing error would occur at the port and then when the manifest was trascribed in Canada or US.

http://www.genealogy.com/88_donna.html
http://genealogy.about.com/od/ellis_island/a/name_change.htm

If she was naturalized citizen than the document would show her surname as well as her maiden name. One would think.