part of
preceded by
neurula stage
NF stage 20
NF stage 21
Nieuwkoop and Faber stage 21, corresponding to an embryo of age 22 hr 30 min at 22-24 Celsius and having the following external morphological criteria: Suture of neural tube completely closed. Delimitation of frontal field by pigment lines. Primary eye vesicles showing through in the form of two separate, obliquely placed oval spots; beginning of protrusion of eyes. Lateral outline of embryo just becoming concave, ventral outline flat. Length: 1.9 - 2.0 mm.
XAO:1000037
xenopus_developmental_stage
NF stage