Genus Microglyphis Dall, 1902

Type species. Actaeon curtulus Dall, 1889 (by original designation); Recent, off Magellan Strait.

Remarks. Shells of this genus are similar to shells of the genus Ringicula, except that they do not develop a thickly callused aperture. This makes them difficult to distinguish from juvenile Ringicula shells, but they exhibit determinate growth characters subtly, such as a thin callus and a subtle change in coiling direction in the aperture. All adult shells of a Microglyphis species typically reach the same size as well. Burn & Thompson (1998) mention that Microglyphis shells have only one columellar fold, but, while this is the case in M. japonica (Habe, 1952), there are also species with two columellar folds, such as M. mazatlantica (Dall, 1908) and M. estuarina (Dall, 1908) .