Marginella is a very large genus of small tropical and temperate sea snails, marine gastropod molluscs in the subfamily Marginellinae of the family Marginellidae, the margin snails. It is the type genus of the family. The shells of species in this genus are rounded, smooth and glossy, with a large aperture that appears to be toothed because it shows the edge of the columellar folds. In many species the shells are colorful. The glossy surface of the shell results from the fact that the mantle covers most of the shell when the animal is active. As is typical in the Neogastropoda, the animal has a long siphon. When the animal is active, the foot extends much further out than the edge of the shell. As is also typical for the Neogastropoda, species in this genus are carnivorous and predatory. Etymology Marginella means "little margin". Shell description The shells of the species in this genus have spires which range from moderately elevated to flattened. The surface of the shell is glossy and porcellaneous, and it is often but not always colourful. The columella has four definite, subequal plaits on its anterior half. The outer lip is thickened, and generally denticulate inside, with distinct teeth or folds. The siphonal canal is not deeply incised. There is no operculum. Description of the soft parts In the living animal, the mantle only partly extends over the shell when the animal is moving. The head is bifurcated, with slender tentacles and eyes in small bulges lateral to the base of tentacles. The siphon is large and protrudes over the head. The foot is large and flat, and when it is extended is slightly longer than the shell. Ecology Distribution This genus is found in tropical and temperate seas worldwide. Species Species within the genus Marginella include: Marginella adamasoides Lussi, 2013 Marginella adamkusi Bozzetti, 1994 Marginella aequinoctialis Boyer & Simbille, 2004 Marginella aikeni V. Veldsman & S. G. Veldsman, 2012 Marginella albidens R. Aiken, 2019 Marginella albocincta Sowerby, 1846 Marginella alborubra Rosado & Monteiro, 2015 Marginella albospira S. G. Veldsman, 2013 Marginella aliwalensis S. G. Veldsman, 2013 Marginella amazona Bavay, 1912 Marginella amirantensis Boyer & Rosado, 2019 Marginella anapaulae Massier, 2004 Marginella anna Jousseaume, 1881 † Marginella antepiperata R. Aiken, 2020 Marginella arcana S. G. Veldsman, Aiken & J. H. Veldsman, 2014 † Marginella arena Cotton, 1949 Marginella aronnax Bouchet & Warén, 1985 Marginella aurantia Lamarck,