part of part of develops from develops from composed primarily of immediate transformation of membrane organ nervous system central nervous system meninx https://upload.wikimedia.org/wikipedia/commons/4/48/Illu_meninges.jpg ZFA:0001355 meningeal layer EFO:0000867 Membrane covering the brain and spinal cord. It is represented by a single layer in fishes, two in amphibians, reptiles and birds and three in mammals (named dura mater, arachnoid and pia mater). [TFD][VHOG] BTO:0000144 FMA:9589 UBERON:0002360 GAID:687 NCIT:C12348 Not consider part of the CNS/neuraxis in FMA meningeal Whereas cyclostomes and fishes only have a single envelope called the primitive meninx, amphibians have two layers, consisting of an outer dura mater which is extremely dense and protective, and a pia-arachnoid or secondary meninx which is more delicate and vascular. Mammals have three meninges: pia mater (which follows all the convolutions of the brain and is the most interior), the arachnoid layer (which is delicate and sends strands to the pia mater), and the dura mater (the outer, more protective meninx). VHOG:0001295 In fishes, the meninges consist of a single membrane, the primitive meninx, wrapped around the brain and spinal cord. With the adoption of terrestrial life, the meninges doubled. In amphibians, reptiles, and birds, the meninges include a thick outer dura mater derived from mesoderm and a thin inner secondary meninx. (...) In mammals, the dura mater persists, but division of the secondary meninx yields both the arachnoid and the pia mater from ectomesoderm.[well established][VHOG] TAO:0001355 Wikipedia:Meninx NLXANAT:090204 layer of meninges CALOHA:TS-1177 MA:0001113 Membrane organ that surrounds the brain and the spinal cord. EMAPA:32660 MAT:0000113 MESH:D008578 meninx primitiva UMLS:C0025285 connective tissue ectoderm-derived structure future meninx meningeal cluster