Its smooth external surface is closely applied between two other meninges, the more superficial dura mater, while the inner roughened surface is separated from the pia mater by the subarachnoid space.
The delicate, spiderweb-like, or arachnoid layer, attached to the inside of the dura, surrounds the brain and spinal cord but does not line the brain down into its folds. In some locations the space is crossed by fine trabeculae.
Athena wove into her web the stories of those who had aroused the anger of the gods, while Arachne chose stories of the errors of the gods.
Enraged at the excellence of the work, Athena tore Arachne's web into pieces. Arachne hanged herself in grief and was transformed by Athena into a spider.
This was adopted as the spider family in science which includes scorpions, mites, and ticks.
The term arachnoid refers to anything that resembles a spider's web.