Qualiter debeat baptizari monstrum nascens cum duobus capitibus.
1. Quaeritur secundo de baptizatione monstri nascentis cum duobus capitibus, qualiter debeat baprizari, utrum sicut unus aut sicut duo.
2. Et videtur quod sicut duo: Quia ubi duo capita, ibi duo corda, quia membra sunt sibi correspondentia. Ergo, si sint duo capita, debent baptizari ut duo.
3. Contra: Monstra nascuntur aliquando cum 24 digitis et cum aliis organis multiplicatis, et tamen non est ibi nisi una anima rationalis. Ergo a simili potest esse in capitibus duobus.
4. [Responsio] Quando monstrum nascitur, aut certum est duas esse animas rationales, aut non. Certum autem est, si sint duo capita et duo colla et duo pectora, erunt per consequens duo corda. In tali casu, sunt baptizandi ut duo. Et quamvis praesumatur quod plures possint simul baptizari dicendo 'ego baptizo vos' etc., tutius tamen est eos baptizare sigillatim. Amplius si est dubium, verbi gratia, si non sint duo capita bene distincta vel duae cervices fundatae in eadem nuca, tunc primo baptizandus est unus, et deinde, illo baptizato, potest aliter dubie baptizari dicendo 'si non es baptizatus, ego baptizo te' etc.
5. Ad obiectum dicendum quod non est simile de monstris omnibus.
"The question concerns the baptism of a monster born with two heads: how should it be baptized, as one or as two?
And it seems that as two: for where there are two heads, there are two hearts, because the members correspond to each other. Therefore, if there are two heads, they should be baptized as two.
But on the contrary, sometimes monsters are born with 24 digits and with other multiple organs, and yet there is only one rational soul there. Therefore there can be a similar case with two heads.
[Response] When a monster is born, either it is certain that there are two rational souls or not. It is certain if there are two heads and two necks and two chests; there will be consequently two hearts. In such a case, they are to be baptized as two. And although it might be presumed that several [people] can be baptized at once by saying 'I baptize you' etc., nevertheless it is safer to baptize them each in turn. If there is a greater doubt, for instance if there are not two heads sufficiently distinct or two necks rooted in the same [trunk?], then the first is to be baptized as one, and then, he being baptized, the other can be conditionally baptized by saying 'if you are not baptized, I baptize you' etc.
To the objection it must be said that not all monsters are the same."
--John Peckham, Quodlibet II Q. 24.
I have to admit, that last line really sells it for me.