part of part of has developmental contribution from has potential to develop into embryo meninx presumptive structure mesenchyme derived from head neural crest future meninx A developing mesenchymal capsule that covers the developing brain and spinal cord and is the precursor of the meningeal cluster. In mammals this gives rise to the arachnoid mater, pia mater and dura mater. In cyclostomes and fishes, the future meninx gives rise to a single meningeal layer, the primitive meninx. EHDAA2:0004453 UBERON:0004065 UBERON:0007645 decide whether to treat the endo and ecto meninx as subtypes or parts of the future meninx meninx primitiva primary meninx primitive meninx primordial meninx the outermost mesenchymal covering of the developing brain and spinal cord that is composed of tough fibrous connective tissue from which the arachnoid mater, pia mater and dura mater are formed[MP:0009726]d uberon meningeal cluster