opus vermiculatum---taken from the latin word 'worm.' It refers to lines of tesserae that snake around a feature in the mosaic. Often 2-3 rows of opus vermiculatum appear like a halo around something in a mosaic picture, helping it stand out from the background.
200-100 BCE Alexandria Egypt. Floor Mosaic Roundel: A Dog & An Overturned Gold Vessel. The quality is fantastic, and this period represents a high point in the mosaic craft in the Greco-Roman world. Many of the tesserae are only 1-2mm across, which allows the mosaicist to achieve a painterly effect. The technique is called "opus vermiculatum", or ‘wormy work’. The Greco-Roman Museum in Alexandria. I can't help but wonder if this wasn't the inspiration for RCA Victor's "His Master's Voice".
-2eS, Pompéi, Maison du Faune, Salle 34 Triclinium 1er STYLE Opus Vermiculatum: EROS ailé avec emblèmes dionysiaques chevauchant un Lion. Emblèmes: Âge d'or (coupe) + Bonheur dionysiaque (vin). Tradition grecque de célébration du Banquet