The species described by Ernst Haeckel as Cytarrocylis cassis is presently considered to be a morpho-type (a variety) of the species formerly known as Petalotricha ampulla (described by Herman Fol), now as Cyttarocylis ampulla. Several forms previously thought to be distinct species of diffferent genera and families appear to be morphs of the polymorphic species, Cyttarocylis ampulla. For details see Bachy et al. 2012.
