Chapter 1: Introduction Keeping Track of Life Prokaryotes and Eukaryotes Where Did Invertebrates Come From? Where Do Invertebrates Live? Changing Views of Invertebrate Phylogeny A Final Introductory Message to the ReaderChapter 2: Systematics, Phylogeny, and Classification Phylogeny, Monophyly, Paraphyly, and Polyphyly Homology Apomorphy and Plesiomorphy Challenges of Phylogenetic Inference Constructing Phylogenies Biological Classification NomenclatureChapter 3: Introduction to the Animal Kingdom: Animal Architecture and Body Plans Body Symmetry Cellularity, Body Size, Germ Layers, and Body Cavities Locomotion and Support Cilia and Flagella Feeding and Digestion Excretion and Osmoregulation Circulation and Gas Exchange Nervous Systems and Sense Organs Bioluminescence Nervous Systems and Body Plans Hormones and Pheromones ReproductionChapter 4: Introduction to the Animal Kingdom: Development, Life Histories, and Origin Evolutionary Developmental Biology: Evo-Devo Eggs and Embryos Life Cycles: Sequences and Strategies The Relationships Between Ontogeny and Phylogeny The Origin of the MetazoaChapter 5: Phylum Porifera: The Sponges Taxonomic History and Classification The Poriferan Body Plan Some Additional Aspects of Sponge Biology Poriferan PhylogenyChapter 6: Two Enigmatic Phyla: Placozoa and Ctenophora (The Comb Jellies) Phylum Ctenophora Taxonomic History and Classification The Ctenophoran Body Plan Ctenophoran PhylogenyChapter 7: Phylum Cnidaria: Anemones, Corals, Jellyfish, and Their Kin Taxonomic History and Classification The Cnidarian Body Plan Cnidarian Evolutionary HistoryChapter 8: A Brief introduction to the Bilateria and Its Major Clades Deuterostomes and ProtostomesChapter 9: Phylum Xenacoelomorpha. Basal Bilaterians The Basal Bilaterian Phylum Xenacoelomorpha Subphylum Acoelomorpha Class Acoela The Acoel Body Plan Class Nemertodermatida The Nemertodermatid Body Plan Subphylum Xenoturbellida The Xenoturbellid Body PlanChapter 10: Protostomia, Spiralia, and the Phylum Dicyemida + Spiralia and Ecdysozoa The Phylum Dicyemida (= Rhombozoa) Anatomy and Biology of Dicyemidans Life CyclesChapter 11: Gnathifera. The Phyla Gnathostomulida, Rotifera (including Acanthocephala), Micrognathozoa, and Chaetognatha + Phylum Gnathostomulida: The Gnathostomulids The Gnathostomulid Body Plan Phylum Rotifera: The Free-Living Rotifers The Rotifer Body Plan Body Cavity, Support, and Locomotion Nervous System and Sense Organs Reproduction and Development Phylum Rotifera, Subclass Acanthocephala: The Acanthocephalans The Acanthocephalan Body Plan Phylum Micrognathozoa: The Micrognathozoans The Micrognathozoan Body Plan Phylum Chaetognatha Chaetognath Classification The Chaetognath Body Plan Reproduction and DevelopmentChapter 12: Platytrochozoa and Two Enigmatic Phyla: Entoprocta and Cycliophora + Phylum Entoprocta: The Entoprocts The Entoproct Body Plan Phylum Cycliophora: The CycliophoransChapter 13: Introduction to the Lophotrochozoa, and the Phylum Mollusca + The Lophotrochoza Phylum Mollusca Taxonomic History and Classification The Molluscan Body Plan Molluscan Evolution and PhylogenyChapter 14: Phylum Nemertea: The Ribbon Worms + Taxonomic History and Classification The Nemertean Body Plan Nemertean PhylogenyChapter 15: Phylum Annelida. The Segmented (and Some Unsegmented) Worms + Taxonomic History and Classification The Annelid Body Plan Sipuncula: The Peanut Worms Sipunculan Classification The Sipunculan Body Plan Thalassematidae: The Spoon Worms Siboglinidae: Vent Worms and Their Kin Siboglinid Taxonomic History The Siboglinid Body Plan Hirudinea: Leeches and Their Relatives The Hirudinean Body Plan Orthonectida: Extremely Simplified Annelids Annelid PhylogenyChapter 16: The Lophophorata: Phyla Phoronida, Bryozoa, and Brachiopoda + Taxonomic History of the Lophophorates The Lophophorate Body Plan Phylum Phoronida: The Phoronids The Phoronid Body Plan Phylum Bryozoa: The Moss Animals The Bryozoan Body Plan Phylum Brachiopoda: The Lamp Shells The Brachiopod Body PlanChapter 17: Rouphozoa: The Phyla Platyhelminthes (Flatworms) and Gastrotricha (Hairy-Bellied Worms) + Introduction to Rouphozoa The Phylum Platyhelminthes (Flatworms) Taxonomic History and Classification The Platyhelminth Body Plan Platyhelminth Phylogeny Phylum Gastrotricha: The Gastrotrichs, or Hairy-Bellied Worms The Gastrotrich Body Plan Reproduction and DevelopmentChapter 18: Introduction to Ecdysozoa: Scalidophora (Phyla Kinorhyncha, Priapula, Loricifera) + Introduction to Ecdysozoa The Scalidophora Phylum Kinorhyncha: The Kinorhynchs, or Mud Dragons The Kinorhynch Body Plan Phylum Priapula: The Priapulans, or Penis Worms Priapulan Body Plan Nervous System and Sense Organs Phylum Loricifera: The LoriciferansChapter 19: Nematoida: Phyla Nematoda and Nematomorpha + Phylum Nematoda: Roundworms Nematode Classification The Nematode Body Plan Life Cycles of Some Parasitic Nematodes Phylum Nematomorpha: Horsehair Worms and Their Kin The Nematomorph Body PlanChapter 20: Panarthropoda and the Emergence of the Arthropods. Tardigrades, Onychophorans, and the Arthropod Body Plan + Phylum Tardigrada The Tardigrade Body Plan Phylum Onychophora The Onychophoran Body Plan An Introduction to the Phylum Arthropoda The Arthropod Body Plan and Arthropodization The Evolution of ArthropodsChapter 21: Phylum Arthropoda. Subphylum Crustacea: Crabs, Shrimps, and Their Kin + Classification of the Crustacea Synopses of Crustacean Taxa The Crustacean Body Plan Crustacean PhylogenyChapter 22: Phylum Arthropoda. Hexapoda: Insects and Their Kin + The Hexapod Body Plan Hexapod EvolutionChapter 23: Phylum Arthropoda. Subphylum Myriapoda: Centipedes, Millipedes, and Their Kin + Myriapod Classification The Myriapod Body Plan Myriapod PhylogenyChapter 24: Phylum Arthropoda.

The Chelicerata + Synopses of Living Chelicerate Groups* The Euchelicerate Body Plan The Class Pycnogonida The Pycnogonid Body Plan Chelicerate PhylogenyChapter 25: Introduction to Deuterostomia, and the Phylum Hemichordata + Introduction to the Deuterostomia Phylum Hemichordata: Acorn Worms and Pterobranchs The Hemichordate Body Plan Class Enteropneusta (Acorn Worms) Class Pterobranchia (Pterobranchs) Hemichordate Fossil Record and PhylogenyChapter 26: The Phylum Echinodermata + The Phylum Echinodermata Taxonomic History and Classification The Echinoderm Body Plan Echinoderm PhylogenyChapter 27: Phylum Chordata: Cephalochordata and Urochordata + Phylum Chordata, Subphylum Cephalochordata: The Lancelets The Cephalochordate Body Plan Phylum Chordata, Subphylum Urochordata: The Tunicates The Tunicate Body Plan Chordate PhylogenyChapter 28: Perspectives on Invertebrate Phylogeny.