The primary externally recognisable feature is the progressive closure of the lens vesicle. The somites in the cervical region are no longer visible and the rapid growth of the brain is striking. The nasal pits start to form.

Absent: auditory hillocks, anterior footplate.

11 dpc (range 10.5-11.25) 
40-44 somite pairs> 
Witschi Stage 25-26 (rat) 
Carnegie Stage 13 (atlas), 14 (atlas), 15 (atlas) (human - stage table)

All scale bars in microns.      
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