“Libri octo Physicorum, traduction latine de la Physique d’Aristote dans la version rédigée par Guillaume de Moerbeke avec le commentaire d’Averroès” is in the Bibliothèque Mazarine in Paris. This Latin manuscript with historiated initials (made by Maître du Méliacin), marginals with grotesques and animals, and some miniatures, is dated to the end 13th century . The manuscript is not available online, but in Liber Floridus I found a (selection of) pages with a malacological topic .
On f. 277v the initial shows a whitish dog and a greyish horse seemingly hunting for a snail in the fields or the woods. The shell is dextral and a few, regularly increasing whorls only. Resolution is too low to see any details of the snail, which may just be stylised.
 BMP, inv. Ms. 3469, 369 ff. http://www.calames.abes.fr/pub/mazarine.aspx#details?id=MAZC10834.