The Lowe and Rand publication of the Morgan fragment of the 5th century Saint-Victor manuscript of the letters of Pliny the Younger has, by great good fortune, images of the transition between books 2 and 3. These include a contents list for book 3, consisting of the recipients, followed by the opening words.
Let’s have a look. Note that you can click on each image for a larger view.
Here’s the end of the first folio of the Morgan fragment — folio 48r, as it was, of the whole manuscript, as the folio number written in a 15th century Italian hand indicates.
So nothing special: “Exp(licit) liber II | Inc(ipit) Lib(er) III.” — “Book 2 ends | Book 3 begins”, plus the usual “feliciter”. Over the page we find on the verso this:
This ends with a line of marks, and then on the verso the text begins:
“C.Plinius Calusio Suo Salutem. Nescio nullum …” Note how the words of the text are not separated in this 5th century manuscript, and the the first two words of the text are as in the table of contents. And also notice … how the full name of the recipient, Calusius Rufus, is NOT given in the title in the text, which simply says “C. Pliny to his (dear) Calusius, greeting”.
Likewise the beginning of the next letter is also in the Morgan fragment, on folio 61:
Ignore the 15th century scribblings at the top, and note the folio number. Here it reads “C. Plinius Maximo suo salutem.” This is the next addressee; Vibius Maximus, as we learn from the index and nowhere else.
The same is true of the next three letters, also present in these few folios, which I will spare you here. The index of addressees gives two names in every case; the actual superscriptio to the letter gives one.
The presence of extra information in the titles means that these cannot be scribal work; they must come down from Pliny himself, unless we propose to imagine some intermediate person locating this information and adding it, which seems unlikely and unnecessary.
The Lowe and Rand publication, bless them, also gives the chapter titles in the only other manuscript that has them. Here they are:
Note that the addressee of the first letter is as it is in the 5th century ms., but the first two words have been moved to the right, to save space.
The titles continue onto the next folio, and then, once again, the superscription of the letter only has the one name, “Calusius”.
Curiously yesterday I discovered a 15th century manuscript of Pliny at the Bibliotheque Nationale site in Paris, shelfmark Ms. Latin 8557. Let’s have a look at the same point in that: