Rondelet wrote this book with the idea of verifying Aristotle, but in it he described many forms of fishes for the first time. The book is an accurate account of his investigation of Mediterranean fishes and marine animals, and Singer says that Fig. 51, illustrating the structure of a sea urchin, is the earliest figure we have of a dissected vertebrate. Rondelet also observed the relationship between embryo and mother in the placental dogfish. Digital facsimile from the Biodiversity Heritage Library at this link.