“Still life of flowers, with toad-stools and butterflies, by a tree trunk” is the title of this oil painting by Rachel Ruysch (1664-1750), made in c. 1682-1684 in Amsterdam. It is now in the collection of the Glasgow Museums [1, 2].
In the central part a snail is visible for the most part. It is a dextral specimen of a Cepaea species, possibly C. hortensis (Müller, 1774).
 GMG, inv. 45.
 Many thanks are due to Tracey MacDonald (Photo Library, Glasgow Museums), for sending me a higher resolution picture of this painting.
 http://explore.rkd.nl/explore/images/193253; http://explore.rkd.nl/explore/artists/69063.