parasitic worms, specifically members of the genera Ascaris and Neoascaris. He found that these worms came from eggs. In addition, Vallisneri worked to elucidate the reproduction of insects, specifically the sawfly. In 1735, the first edition of Carl Linnaeus' Systema Naturae was published; this work included information on both insects and intestinal worms. However, the tenth edition is considered the true starting point for the modern classification scheme for living things today. Linnaeus' universal system of classification made a system based on binomial nomenclature, but included higher levels of classification than simply the genus and species names. Systema Naturae was an investigation into the biodiversity on Earth. However, because it was based only on very few characters, the system developed by Linnaeus was an artificial one. The book also included descriptions of the organisms named inside of it. In 1859, Charles Darwin's On the Origin of Species was published. In this book, he described his theory of evolution by natural selection. Both the work of Darwin and his contemporary, Alfred Russel Wallace —who was also working on the theory of evolution—were informed by the careful study of insects. In addition, Darwin collected many species of invertebrate during his time aboard ; many of the specimens collected were insects. Using these collections, he was able to study sexual dimorphism, geographic distribution of species, and mimicry; all of these concepts influenced Darwin's theory of evolution. Unfortunately, a firm popular belief in the immutability of species was a major hurdle in the acceptance of the theory. 20th century Classification in the twentieth century shifted toward a focus on evolutionary relationships over morphological description. The development of phylogenetics and systematics based on this study is credited to Willi Hennig, a German entomologist. In 1966, his Phylogenetic Systematics was published; inside, Hennig redefined the goals of systematic schemes for classifying living things. He proposed that the focus be on evolutionary relationships over similar morphological features. He also defined monophyly and included his ideas about hierarchical classification. Though Hennig did not include information on outgroup comparison, he was apparently aware of the practice, which is considered important to today's systematic research. Notable invertebrates The Japanese spider crab (Arthropoda: Macrocheira kaempferi) is one of the world's largest arthropods. The Japanese spider crab is largest known species of crab and may live up to 100 years. With a leg span of that can reach four feet, it has