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
To a Butterfly of "Poems in Two Volumes" entitled "Moods of my Mind", in which he grouped together his most deeply felt lyrics. Others included "The Sparrow's Nest", in which he says of Dorothy "She gave me eyes, she gave me ears", and "I Wandered Lonely as a Cloud", based closely on an entry in Dorothy's journal following another walk together. To a Butterfly "To a Butterfly" is a lyric poem written by William Wordsworth at Town End, Grasmere, in 1802. It was first published in the collection "Poems in Two Volumes" in 1807. Wordsworth wrote two poems addressing a butterfly, of which