个科，过往曾属于腹足纲之下不同的分类。早期的作者（例如：J.E. Gray, 1840）曾以为异鳃类只有海洋物种，概念上属于介乎后鳃类和肺螺类之间其他物种的边缘分类。The (sometimes recognized) categoryHeterostrophawithin the Heterobranchia, which includes such families as Architectonicidae, the sundial or staircase snails, is primari