The dura mater has two layers, or lamellae: The superficial layer (also called the periosteal layer), which serves as the skull's inner periosteum, called the endocranium; and a deep layer called the meningeal layer; the actual dura mater.
The term thagomizer was coined by Gary Larson in humor, in a 1982 Far Side comic strip, in which a group of cavemen in a faux-modern lecture hall are taught by their caveman professor that the spikes on a Stegosaur's tail are so named after the late Thag Simmons.
Gary Larson. Born in Tacoma, Washington in 1950, cartoonist and author of The Far Side Gary Larson was an avid reader of comics himself from a young age. Art wasn't his first love, however, when he was young. It was science, and more especially, biology.