 The copulatory apparatus has a permanent penis and the ovovitelline ducts enter the female atrium from below.This definition, however, is incomplete regarding the anatomical features currently considered in the definition of planarian genera and "Gigantea" is certainly a heterogeneous genus.The name "Gigantea" (Latin for "giant") comes from the specific epithet, "gigantea", of the type-species, originally described as "Geoplana gigantea" due to its large size.