by William Swainson, Zoological Illustrations Series II… (1829)
“ In Voluta and Mitra, the two typical groups of this family, the variations of form are so striking, and the species so numerous, that we readily assent to the plan, proposed by others, of further dividing them into genera: but in the aberrant group, containing Oliva, Ancillaria, and Marginella, the forms are less diversified, and the species fewer; the minor divisions may therefore, for the present, be termed sub-genera. The approximation of Marginella to Voluta has frequently been stated. ”
