In the library of the Free University of Amsterdam, a book of hours is present that was made in 1520 for the family Van Hoof. The illustrations were largely made by Cornelia van Wulfschkerke, a Carmelite nun who worked in a cloister in Brugues, Flanders. [1, 2]
The book is decorated with 15 miniatures and borders or marginalia, of which most are attributed to Cornelia van Wulfschkerke. The illustrations are relatively coarse, also given the size of the book (152 x 115 mm).
At a number of pages snails show up, all are ‘2D squashed’  and stylised; they occur as singletons on a page, which is otherwise illuminated with flowers or other animals.
f. 001v: in the middle-upper margin a snail is figured in side-view, with its head pointing left. The head does remind me somewhat to a fish, but given the context of the other figures in this manuscript it is undoubtedly a snail. Possibly the up- and downwards curved appendices of the head represent the tentacles. The body is light greyish and the shell, seen in dorsal view, is left-coiled and yellow-orange in colour, with a darker spiral band and some striation indicated. Although the shape of the last whorl is not quite natural, it may be that this stylised snail was inspired by a Cepaea species (see also below).
f. 078v: also in the upper margin, a similar snail as the previous is seen, his head pointed to the right. The shell is right-coiled and yellowish coloured, the periphery and suture in reddish shades, as is some striation.
f. 091r: upper margin, in the middle, the snail is pointing to the right. The shell is yellow, but this time with dark spiral bands characteristic for Cepaea cf. nemoralis (Linnaeus, 1758). One spiral line is dotted and reddish, which is, however, not quite characteristic for this species. The body of the animal is light grey with some darker spots near the foot.
f. 117r: upper margin, in the middle, the snail is pointed to the right; however, the shell – yellowish-orange with reddish contours and suture – is left-coiled. The body is light grey with darker spots.
f. 142v: in the lower-right corner of a gold-coloured border, a snail is figured with the head pointed to the left, the shell is left-coiled, making an unnatural impression; shell and body are similar to the previous figure.
f. 159r: in the middle, lower border, on a greenish-bluish background, a brownish snail may be seen, which is pointed to the right and right-coloured. The shell has several spirally arranged darker, longitudinal spots. Although a stylised snail, it is not impossible that this figure was inspired by the species Cornu aspersum (Müller, 1774).
The fact that this artist lived in a cloister in Brugues, make is likely that she figured locally available species. Snails were moreover usually present in cloisters and their gardens as they were, in the Catholic tradition, accepted as food during fast. This may explain partially the distribution of some European species 
The help of Dr. Dolf van Bruggen in locating Geyer’s reference is thankfully acknowledged.
 VUA, University library, XV.05502, 185 ff. http://bit.ly/19d1ZZs 9 (4.i.2014).
 Heijting, W. (2007). Catalogus van de handschriften in de Universiteitsbibliotheek Vrije Universiteit Amsterdam: 1–223. Eon, Amstelveen.
 With this term I denote the 3D shape of a snail transferred to a 2D plane, usually with the body in side view and the shell in dorsal view (i.e. from the top); in reality this top is at some angle to the side view plane, depending on the shape of the shell (ranging from elongate to globose to discoid).
 “Die Schnecke haelt sich an die menschlichen Siedlungen und verdankt ihre Verbreitung der Verschleppung mit Gartengewaechsen und der absichtlichen Verpflanzung als Fastenspeise nach Mittleuropa und weiterhin in alle Erdteile.” (Geyer, D., 1927. Unsere Land- und Suesswasser-Mollusken. Einfuehrung in die Molluskenfauna Deutschlands. Stuttgart, 3rd ed.: p. 94 sub Helix aspersa).