This snail-rich manuscript is in the Bibliothèque Université de Liège. It is a Book of Hours, for use at Utrecht, made ca. 1522 in the Netherlands, and is written partly in Latin, partly in Dutch. There are a number of miniatures, and the borders are made in Ghent-Bruges style [1, 2, 3].
All snails in this manuscript are stylized and modelled after an unidentifiable species. The shells are figured with relatively few whorls (2+), the last one widening, a thickened lip at the aperture. All shells are in various shades of brown. Some shells show streaks in the colour pattern, suggesting axial ribs. The snails are shown with two tentacles only, most without tail, and in 2D-squased mode.
Folio 014v shows a miniature bordered with figures of flowers, a caterpillar, a butterfly, a bird, and a dextral snail. The snail is in the middle part of the left-hand border.
The border of folio 015r is illuminated with flowers, a caterpillar, and a dextral snail. The position of this snail is in the right-hand border.
Folio 047r has a border with mostly flowers, a caterpillar (?), and a dextral snail.
The border on folio 051r has several flowers (roses?), a butterfly, and a sinistral snail.
Folio 073r is illuminated with a border with Lathyrus flowers, some insects, a peacock and a dextral snail.
On folio 109v six snails and one shell are present. It is the largest number of snails seen together so far in a medieval manuscript. From upper left to lower right in the border can be seen: two sinistral specimens, a dextral one with also the tail visible (a bird on top of the shell), a sinistral one, a dextral shell, and two snails which are sinistral ones again.
On folio 113r a border with flowers, a bird and a snail is seen. The snail has a sinistral shell.
Finally, on folio 128r in the upper border a dextral snail is included.
 ULL, Ms. W. 31, [vi +] 153 ff. (f. 143-153 blank). http://donum.ulg.ac.be/peps/MsW031/.
 Description at http://tinyurl.com/mtpjj2e.
 Thanks to Bxknits who suggested in comments one of the pages here.