APLS XPI

The pink and blue greyhound is curious enough, but I am also interested in these abbreviation marks that appear to weave through the letters.

Epistolae sancti Pauli et Evangelia sancti Matthaei cum glosa
Source: gallica.bnf.fr

Bibliothèque nationale de France, Département des manuscrits, Latin 14409, fol. 57r.