This addendum is dedicated to some paintings which I saw during my recent visit to Rijksmuseum Twenthe, Enschedé (Netherlands).
I found them in the permanent exhibition, entitled ‘Way to Paradise’, where a number of still lifes were together with some (to me unrelated) objects. Three of these still lifes had a shells or a snail depicted.
The first is a painting by Johannes Bosschaert (ca. 1606/1608–1628), who worked in Haarlem and Dordrecht . The painting shows four shells at lower right, one of which is a land snail: Polymita picta. Dated 1626, this work was previously in the Kröller Muller museum .
The second is by Balthasar van der Ast is dated ca. 1625, and shows a number of shells. Among these one is probably an Achatinia species. As the painting was high up the wall, the detail has been taken from the picture in the RKD database .
The third painting  is by Willem van Leen (1753–1825), who worked in Dordrecht, Paris and Delfshaven (Rotterdam); in the latter place this work was made in 1798. The painting shows fruit, dead birds, and a snail. This snail is clearly a Cepaea species; the body is quite intense black, which is rather uncommon.
 inv. NK 2695. RKD work 17210 (https://rkd.nl/explore/images/17210).