A well known picture on the internet, this detail comes from an oil paint in the Palazzo Ducale, Venice. This work was made in 1595 and is attributed to Herri (met de) Bles a.k.a. Civetta [1, 2]. It is a detailed view of the Hell (“Inferno”), with this malacomorph hybrid in the central bottom part. The shell is dextral with many spots and fine traces of spiral lines.
 PDV, inv. 269. http://bit.ly/1qmbLgR.
 According to http://en.wikipedia.org/wiki/Herri_met_de_Bles, this Flemish painter lived from c. 1510-c. 1555/1560; given these dates it seems impossible that made this work if the year given in the catalogue is correct. Since he is “believed to be a court painter for the d’Este Dukes of Ferrara”, it is likely that this work originated there.