Pituitary control of metamorphosis in the southern hemisphere lamprey, Geotria australis.

Partial hypophysectomy of pretransforming ammocoetes of the southern hemisphere lamprey, Geotria australis, shows that removal of the rostral pars distalis completely inhibits metamorphosis, whereas removal of the caudal pars distalis allows metamorphosis to begin but not to proceed to completion. Studies on the activity and identification of cell types within these two lobes of the pituitary of other species are related to this pituitary control over metamorphosis in lampreys.