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.
The series remains a fixture in popular culture long after Larsonâs retirement. By his count there are 4,337 Far Side cartoons, the first published on December 31, 1979, the last on January 1, 1995. What is surprising is the extent of the religious material found in these pages.