By the end of the Middle Ages religious motifs were still very much ‘en vogue‘ in visual arts. Italian painters were especially good at this theme, and one of them was Francesco del Cossa (c. 1430/1435–1477). He worked in Ferrara in northern Italy and made c. 1470/1472 the work ‘Annuncio’, which is now in the Staatliche Kunstsammlungen in Dresden. 
You see in the foreground a snail on the move to the right; you can’t deny, it’s so obvious. Catching the eye… But to my knowledge this is the first painting where a snail is pictured in such great detail if you zoom into it. Art historians have attached different symbolic meanings to snails; in the case of this painting the iconographic snail would exemplifying “the perpetual virginity of Mary” . But I also found a different, well-written opinion in a book by the French art historian Aresse (see ), who believes the snail “makes you understand that you are seeing nothing in what you are looking at”. Food for art historians…
Anyway, what species are we seeing here? According to Aresse this is “a good old Burgundy snail” [i.e. Helix pomatia]. But I don’t think it is what Aresse thought he was seeing. Why would a painter in northern Italy use a French species he might even not have known? Would it be not more plausible to use a species that could be locally obtained? If so, we need to look at the Italian malacofauna. In one of Cesari’s papers on Italian land snails  I found a shell very similar to the one in Cossa’s work; pl. 5 fig. 1 shows Helix cincta Müller, 1774 from the same area where Cossa worked. The same broad pale band along the suture and a small one on the periphery. That is what I see in this snail.
 SKD, Gal. 43. http://bit.ly/1cIcgrZ (25.x.2013).
 Ettlinger, H.S. (1978). The virgin snail. — Journal of the Warburg and Courtauld Institutes 41: 316.
 Waters, A. (2008). The snail’s gaze. Available at http://intranslation.brooklynrail.org/french/the-snail’s-gaze.
 Cesari, P. (1978). La malacofauna del territorio Italiano (Note di aggiornamento e diffusione conoscitiva), 1o contributo: il genere Helix. — Conchiglie (Milano) 14: 35–90.