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 tail (goldfish) Butterfly tail (goldfish) The Butterfly tail (Man Shek-hay, 1993) or Butterfly telescope (Teichfischer, 1994) is a variety of goldfish that is distinguished by the butterfly-shaped caudal fins when viewed from above. It is a variety that has only recently been deemed a major lineage by a few published works. Because this tail conformation is commonly bred into the telescope eye goldfish, the term "butterfly tail" is just short for the many names this variety has such as Butterfly Tail Telescope, Butterfly Tail Demekin, Butterfly Tail Moor and Top view Telescope (TVT). The butterfly tail is a variant form of the