![](/drem/stage21/labels/S31L.gif)
![alar plate of mesencephalon, artifact space(s), cerebral aqueduct (mesocoele), head mesenchyme, osteogenic layer, roof plate of mesencephalon, subarachnoid space, surface ectoderm](/drem/stage21/Z0/S31N.jpg)
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Carnegie Embryo #4090 | Location: 2-15
Keywords: alar plate of mesencephalon, artifact space(s), cerebral aqueduct (mesocoele), head mesenchyme, osteogenic layer, roof plate of mesencephalon, subarachnoid space, surface ectoderm
Source: The Virtual Human Embryo.