Threatened arthropods and described. The total number of living arthropod species is probably in the tens of millions. One conservative estimate puts the number of arthropod species in tropical forests alone at six to nine million species. As a consequence of all of the above, most published estimates of the total number of endangered insects and arachnids are probably low by at least an order of magnitude. Conservatively at least eighty percent of all living animal species are arthropods. Since arthropods constitute the majority of the faunal biomass on Earth, their role is vital to the survival of large numbers of insectivores
History of Animals especially the wryneck, fishes and snakes. Book III The internal organs, including generative system, veins, sinews, bone etc. He moves on to the blood, bone marrow, milk including rennet and cheese, and semen. Book IV Animals without blood (invertebrates) – cephalopods, crustaceans, etc. In chapter 8, he describes the sense organs of animals. Chapter 10 considers sleep and whether it occurs in fish. Books V and VI Reproduction, spontaneous and sexual of marine invertebrates, birds, quadrupeds, snakes, fish, and terrestrial arthropods including ichneumon wasps, bees, ants, scorpions, spiders, and grasshoppers. Book VII Reproduction of man, including puberty, conception, pregnancy, lactation,