Note: A scholar who works on Bonetus sent me an email correcting my punctuation, translation, and bio. So thanks are in order. It's always nice to know that when I post these translations of obscure Scotist texts that someone actually reads them!
Metaphysica III c. 3 (ed. Venezia 1505, f. 19vb-20ra):
Circa hunc terminum 'formalitas' vel 'quiditas' quod sit et quod non. Et quotiens dicuntur est insistendum. Omne illud est 'formalitas' vel 'quiditas' (quod idem est) quod additum alteri variat rationem formalem ipsius, scilicet constituti ex illo et altero cum additur, vel per se est inclusum in ratione formali alicuius.
Ex primo sequitur quod omnes differentiae superiores et mediae et specificae spectant ad quiditatem, quia additae quidditati contrahibili variant rationem formalem constitutorum per illam, ut hominis et bruti. Ex hoc sequitur quod differentiae individuales non sunt quiditates nec formalitates, cum non varient rationem formalem per illas constitutorum, immo constituta per illas sunt eiusdem rationis et speciei.
Ex secundo sequitur quod omne contrahibile per se per differentiam aliquam cum qua facit per se unum est quiditas vel formalitas, ut prima quidditas et primum contrahibile et prima omnino formalitas sit ens in quantum ens, deinde praedicamenta et sic descendendo usque ad speciem specialissimam, que est ultima quiditas per se includens omnes superiores in linea predicamentali.Translation:
...everything is a 'formality' (or a 'quiddity', which means the same) that either: 1) when it (a) is added to another (b), it (a) changes the formal description [ratio] of it, that is, of what is constituted from that thing (a) and that other thing (b) when (a) is added to (b); or 2) is per se included in the formal description of something.
From 1) it follows that all superior, middle and specific differences pertain to the quiddity, because when they are added to a contractible quiddity they alter the formal description of what it constitutes, such as of 'human being' or 'beast'. From this it follows that individual differences are neither quiddities nor formalities, since they do not alter the formal description of the things they constitute, rather the things they constitute have the same description and species.
From 2) it follows that everything that is per se contractible by some difference with which it makes a per se unity is a quiddity or formality, as the first quiddity and the first contractible and the absolutely first formality is being qua being, and then the categories, and so descending until the most specific species, which is the final quiddity including per se all the quiddities above it in the predicamental line (or sequence).