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 was born in Washington in 1950 and started cartooning during the mid 70s. He evolved into a serious cartoonist when in 1980 some of his panels were accepted by âSan Francisco Chronicleâ and it was the birth of âThe Far Sideâ series.