EMBRYONIC PERIOD
embryonic period: translation
the time from union of gametes (or in gynogenetic fishes the triggering of cell division) until exogenous nutrition. This period is characterised by endogenous nutrition from the yolk of the ovum (or in viviparous fishes from an ovarian secretion or combination of yolk and secretion). This period is divided into three phases:- cleavage (beginning of development to beginning of organogenesis), embryonic (organogensis) and eleutheroembryonic (hatching to external feeding after all or most of the yolk is absorbed)