"The Origin of Vertebrates" by Walter Holbrook Gaskell is a scientific publication written in the early 20th century. This work delves into the evolutionary history and anatomical characteristics of vertebrates, particularly examining their origins from invertebrate ancestors. Gaskell focuses on the central nervous system and various anatomical features that illustrate the evolutionary connection between vertebrates and their ancestral forms. The opening of the text presents an introduction where Gaskell reflects on the necessity of interdisciplinary approaches in scientific inquiry, specifically the interplay between physiology and comparative anatomy. He recounts the development of his own ideas, rooted in years of physiological research, which led him to explore the origins of vertebrates through various lines of evidence. Among these, he emphasizes the importance of studying the larval form of the lamprey, or Ammocoetes, as it provides crucial insights into the anatomical similarities shared with ancient vertebrates and the evolutionary transitions that have occurred over time. (This is an automatically generated summary.)