How the Snake Lost Its Legs fly embryo. His books on evolutionary developmental biology (evo-devo) include "Imaginal Discs: The Genetic and Cellular Logic of Pattern Formation" (2002), "Quirks of Human Anatomy: An Evo-Devo Look at the Human Body" (2009), and "Deep Homology? Uncanny Similarities of Humans and Flies Uncovered by Evo-Devo" (2017). In Held's view, "Quirks", "Snake", and "Deep Homology" form a trilogy on evo-devo. "How the Snake Lost Its Legs" is ostensibly organised into six chapters, but in effect into three parts. The first chapter serves as an introduction and overview. The next four chapters provide what Held calls "the meatier aspects of evo-devo" with
Butterfly kick Butterfly kick A butterfly kick or horse kick (xuànzi 旋子 circle) is a jumping kick in martial arts such as modern wushu and taekwondo and capoeira. In certain changchuan styles, this kick is known as Swallow Kick (Yianzi tui). Although the specific nature of the kick varies, it is generally composed of a twist of the body while both legs are lifted from the ground and swung around, while the torso remains as horizontal as possible. In action cinema it is often seen as a kick used to "cut a swathe" through multiple opponents. In traditional Chinese longfist, it is