Appearance of cranial flexure and torsion.

Formation of 28 pair of somites.

Formation of 11 neuromeres.

Development of auditory and optic vesicle.

Formation of secondary constrictions in the brain.

Twisting of heart, formation of chambers, completion of vitellina circulatory system and development of intraembryonic blood vessel.

Formation of pronephric kidney, thyroid and liver.