This painting by Pieter Cornelisz. van Slingelandt (1640–1691) is dated 1688 and entitled “Portrait of a Man with a Watch”; now in the Rijksmuseum, Amsterdam .
Van Slingelandt worked as painter in Leiden. This painting shows some similarity to the painting “Violin player and pouring woman in a window”, which is attributed to Willem van Mieris [working also in Leiden, 1684–1747] and was (formerly?) in the Staatliche Kunstsammlungen, Dresden ; however, it does not appear in the online catalogue. Both paintings are mentioned in Dittrich & Dittrich (2004) as examples of symbolism where the snail represents Acedia (see also ).
In this painting the snail is on the window sill. It is likely a Cepaea species.