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.
Added to Your Check-Ins. Tales from the Far Side (1994) A series of Gary Larsen's Far Side gags are turned into short animated gags, such as a Frankenstein cow; an insect airline's in-flight movie; deer, hunters, and UFOs; wolf home-movies; ...