"For example, James Barbut wrote in his 1783 book The genera Vermium exemplified by various specimens of the animals contained in the orders of the Intestina et Mollusca Linnaei that the slug Arion ater "is an [sic] hermaphrodite, both sexes being in each individual, and both in the coitus impregnate, and are impregnated, at the same time.""