The different members, however, of the family present, as Schiodte remarks, "a long series of forms exhibiting a gradual transition from Hippoglossus pinguis, which does not in any considerable degree alter the shape in which it leaves the ovum, to the soles, which are entirely thrown to one side."
Hala ere, familiako kide ezberdinek, Schiödte-k seinalatzen duen moduan, honako hau aurkezten dute: "mailakako iragaitza erakusten duen forma-serie luzea, arrautza uztean duen formatik asko aldatzen ez den Hippoglossus pinguisetik hasi, eta erabat albo batera etzanik egoten den lengoraduraino doana".