On the site of the Netherlands Institute for Art History (RKD) one can find an immense source of data on artists and their works. That is where our search initially began. Later more on what I’ve found there. But meanwhile also some digging in the archives (here indicated as RKD Arch.) has been done with the help of Susanne de Heer.
One of the flower still-lives we’ve found is from Willem van Aelst (1627-1683). He painted mainly still-lives in oil paint, and worked in Delft, France, Florence and Amsterdam. 
This painting , made in 1675 in his Amsterdam period, shows a glass vase on a ledge with flowers, a butterfly, beetle and – in the lower right-hand corner – a snail. All are very accurately drawn.
The snail is a uniformly yellowish coloured specimen of Cepea nemoralis (L., 1758).
 http://bit.ly/1a9SANv (8.i.2014).
 RKD archive, 624 Anoniem-Ast, Aelst (1675).