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Ontology Definition: TS18

Theiler Stage 18 - Closure of lens vesicle


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 - stage table)
Carnegie - Stage 13 , Stage 14 , Stage 15 , (human - stage table)
Virtual Human Embryo - Stage 13 , Stage 14 , Stage 15

All scale bars in microns

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