Under the title Commentarium de ratione metrorum this volume provides a critical edition (1–64), translation into Italian (65–88) and commentary (89–161) on a stratified compilation of discussions about the quantity of syllables (in the presence of particular consonant clusters, synaloepha, cases of dichronism, nominal and verbal endings, etc.). The textual evolution of the corpus goes back to the middle of the fourth century and perhaps originated close to Donatus' Artes, which do not deal with prosody. The forty-one surviving manuscripts (two of these are descripti) are variable in textual extension, arrangement and single readings, justifying previous editors' choice (with the partial exception of Parrasio) to separate De ratione metrorum (pp. 5–30 = GL VI, 216–28), attributed to Maximus Victorinus, from De finalibus (pp. 31–64 = GL VI, 229–40), attributed to Metrorius (Maxim(in)us). In the manuscripts, including Neap. Lat. 2, De ratione metrorum is almost always followed by De finalibus, but the presence of a second inscriptio, transmitted in various forms (and wrongly relegated by Corazza to the apparatus on p. 31.1), suggests that the two texts were not considered as a single textbook but as a scholastic collection (see xliii). Besides, De finalibus offers a more detailed treatment of the final section of De ratione metrorum dealing with the final syllables only of the categories nomen and verbum (transmitted in alternative orders in the sub-families ϕ and τ).
Ten manuscripts preserve De finalibus alone, without De ratione metrorum and the marginally relevant chapter de caesuris (which is also preserved as an addendum to other treatises (xlii n. 5)). Shared variants (cxxxvii–cxl) distinguish this version α from the version β which is preserved after De ratione metrorum. Only Sang. 876 (eighth to ninth century) contains the introductory chapters about the classification of letters and syllables (31–5), but it separates them from the rest of the treatise by the Ad Basilium amicum Sergii (GL VI, 240. 11-242). On the other hand, Ad Basilium simply replaces such chapters in Pal. Lat. 1753 (eighth to ninth century), as well as in Par. Lat. 13205 (ninth century) in which Ad Basilium (broken up by GL VI, 241. 3) is however followed by the words Servivvs [sic] Aquilino salvtem (p. cv). In Lev. 2. 1 (eighth century) and in Oxon. Magd. Coll. 64 (fourteenth century) De finalibus is inserted into the text of Book II of Explanationes in Donatum (see pp. cviff.); in Barcill. Ripol. 46 (ninth to tenth century) and Bern. 207 (eighth century) it is inserted into the middle of Book I of Donatus' Ars maior, between De syllaba and De pedibus (p. lxxxvii); in Oxon. Add. C 144 (eleventh century) it is divided up and included in the relevant sections throughout the Ars minor (p. cii). In the end, version α is preserved as an independent text only in Berol. Diez. B Sant. 66 and Par. Lat. 7530, both from the ninth century, as well as in Pal. Lat. 1753, Par. Lat. 13205 and Sang. 876, where introductory sections precede it; these appear to record the earliest stage of transmission, when notes on Donatus' Artes were gathered together to form a single independent treatise De finalibus (p. xlii). But, given the absence of shared errors, it is not necessary to conclude with C. that Sang. 876 acquired its chapters on letters and syllables from a manuscript of version β belonging to the branch γ, which preserves only the introductory chapters of De finalibus after De ratione metrorum (p. xlv n. 11). In the same way as texts such as Ad Basilium and the so-called Regulae de finalibus are preserved in Lav. 2.1 (Appendix I, 168–70), these chapters on letters and syllables must have circulated independently, as occurs in Neap. Lat. IV A 34, ff. 144r–v.
Following the Commentarium, Appendix I contains a critical edition of five shorter works. Four of these have already been edited by C. in F. Gasti (ed.), Grammatica e grammatici latini (2003), 93ff., but the prefatory letter of the fragmentary De finalibus of Coronatus and the De finalibus syllabis omnium partium were previously unedited. Appendix II contains lectiones singulares from the manuscripts of De ratione metrorum and De finalibus (183–218), a selection of frequent variants (219–23) and a list of differences from Keil's edition (224–31).
The edition shows diligence and critical judgement. There is a substantial bibliography (ix–xxxviii). The Introduction (xxxix–cxliii), in offering a reconstruction of the history of the text before the description of the manuscripts, unfortunately forces the reader to flick constantly between different sections.
