The adult might also become fitted for sites or habits, in which organs of locomotion or of the senses, etc., would be useless; and in this case the metamorphosis would be retrograde.
Heldua ere, bere aldetik, baliteke ibil-organoak, zentzu-organoak eta abarrak emendiorik gabekoak lituzkeen leku edo azturetara egokitzera iristea; eta kasu honetan metamorfosia atzerapausoa litzateke.