Why does Jerome not cite the Vulgate of the Pericope adulterae?

Jerome’s remarks on the story of the adulterous woman in his tract Against the Pelagians (415) are sometimes cited as evidence for its existence at the time of his revision of the gospels in 384. In an earlier post though, I pointed out that Against the Pelagians was written some thirty years after the Vulgate gospels and hence probably cannot be considered evidence for the state of the text in the early 380’s, at the time of Jerome’s Vulgate project.

The question remains of course whether Jerome was looking back to this earlier time. In light of this possibility, it is noteworthy that Jerome does not cite the Vulgate text in his remarks to the Pelagians. Consider:

Against the Pelagians (CCSL 80) Vulgate (R. Weber)
At Iesus inclinus digito scribebat in terra (v. 6)

Qui sine peccato est uestrum, primus mittat super eam lapidem (v. 7)

Vbi sunt? Nemo te condemnauit? Quae ait: Nullus, Domine. Responditque ei Iesus: neque ego te condemno. Vade, et amodo noli peccare. (vv. 10-11)

Iesus autem inclinans se deorsum digito scribebat in terra (v. 6)

qui sine peccato est vestrum primus in illam lapidem mittat (v. 7)

ubi sunt nemo te condemnavit quae dixit nemo Domine dixit autem Iesus nec ego te condemnabo vade et amplius iam noli peccare (vv. 10-11)

Clearly Jerome’s three citations of the pericope adulterae in Adversus Pelagianos attest some significant discrepancies in comparison with the Vulgate. The differences in vv. 10-11 seem hardest to explain. After all, it seems odd that Jerome would default to a different form of the woman’s two-word response, “No one, Lord,” or the memorable pronouncement, “Neither do I condemn you,” even if he were paraphrasing or citing from memory.