This is a short period with turning initiated in embryos with 6-8 pairs of somites and usually completed in embryos with 14-16 pairs of somites. The first branchial arch has maxillary and mandibular components but the maxillary process is not visible until later (TS16). A second branchial arch is now evident. There is evidence of regionalisation of the heart and the neural tube is closed from a point opposite the outflow tract to the proximal part of the tail.

Absent: 3rd branchial arch.

8.5 dpc (range 8-9.25)
8-12 somite pairs

All scale bars in microns

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