"Ten Little Niggers" in the Bodleian broadside attributed to Green differs from the rhyme "Ten Little Nigger Boys" in "The Oxford Nursery Rhyme Book," Iona and Peter Opie, p. 193, and also differs from the version "Ten Little Niggers" posted by Wolfgang (and also attributed to Green).
The version in the Agatha Christie mystery is the one posted by Wolfgang.

The rhyme in the "Oxford Nursery Rhyme Book" changes the cumbersome "One chopped himself in halves" to "One chopped himself in half,..."
The last verse is changed by the Opies to:
"One little nigger boy living all alone;
He got married, and then there were none."
(A fate worse than hanging?)