STAGE 17. Age 18 ¾ h.; length 1.5 -1.6 mm.

Ext. Crit.: *Late neural fold stage*. *Anterior part of neural plate oblong triangular*, angles formed by eye anlagen. Neural folds approaching each other from blastopore up to anterior trunk region.

Int. Crit.: In anterior half of embryo neural crest material loacted at lateral edges of neural anlage; caudal half sharp delimiataion of neural crest material from neural plate (s.s.). *Eye anlagen showing first signs of lateral evagination*.
*First indications of somite segregation*, but still continuous with myocoelic cavity.