17.1 Introduction
17.2 Phylogeny and Classification
17.3 Morphology
17.3.1 Shell
17.3.2 Head, Arms, and Funnel
17.3.2.1 Embryological Evidence for the Derivation of Head Structures
17.3.3 Epidermis (Skin)
17.3.4 Head and Funnel Retractor Muscles
17.3.4.1 Muscular Attachments, Shell Growth and the Addition of Septa
17.3.5 The Fossil Record of Soft Tissues
17.3.6 Mantle Wall
17.3.7 Mantle Cavity
17.4 Biology and Ecology
17.4.1 Habits and Habitats
17.4.1.1 The Habits and Habitats of Extinct Ectocochleate Cephalopods
17.4.2 Locomotion and Buoyancy
17.4.2.1 Locomotion
17.4.2.2 Buoyancy
17.4.2.3 The Shell as a Buoyancy Device
17.4.2.4 Other Buoyancy Strategies
17.4.3 The Ink Sac and Inking
17.4.4 Colour Changes – Chromatophores and Other Special Skin Structures
17.4.4.1 Chromatophores
17.4.4.2 Structural Reflectors (Iridophores, Silvery Reflectors, and Leucophores)
17.4.5 Luminescent Organs
17.5 Digestive System
17.5.1 The Jaws
17.5.2 The Radula
17.5.3 Feeding
17.6 Renopericardial System
17.7 Courtship, Reproduction, Development, and Growth
17.7.1 Reproductive System
17.7.1.1 Sexual Characters and Sexual Dimorphism
17.7.2 Courtship and Mating
17.7.3 Life History
17.7.3.1 Spawn and Parental Care
17.7.3.2 Development
17.7.4 The Nervous System, Sense Organs, and Behaviour
17.7.5 The Endocrine System
17.7.6 Learning and Intelligence
17.7.7 Behaviour
17.7.8 Symbiotic Relationships
17.7.9 Predators
17.8 Economic Values
17.9 The Origin of Cephalopods
17.10 Diversity and Fossil History
17.10.1 The Ordovician Radiation and Beyond
17.11 The Major Groups of Cephalopoda
17.11.1 The Nautiliforms
17.11.1.1 Ellesmeroceratia and Plectronoceratia
17.11.1.2 Orthoceratia
17.11.1.3 Discosorida
17.11.1.4 Endoceratia
17.11.1.5 Actinoceratia
17.11.1.6 Nautilia
17.12 Bactritia and Ammonitia (= Ammonoidea)
17.12.1 Bactritia (= Bactritoidea)
17.12.2 Ammonitia (Ammonites)
17.12.2.1 The Embryonic Shell (Ammonitella)
17.12.2.2 Ammonite Sutural Patterns
17.12.2.3 Life Habits
17.12.2.4 Aptychus and Jaws
17.12.2.5 Phylogeny, Classification, Diversity, and Fossil History of Ammonites
17.12.2.6 The Major Groups of Ammonites
17.13 Coleoida
17.13.1 Phylogeny, Classification, Diversity, and Fossil History
17.13.1.1 Belemnitidia (The Belemnites)
17.13.1.2 Decabrachia
17.13.1.3 Squid – A Grade Not a Clade – The Myopsida, Oegopsida, Bathyteuthoidea (‘Teuthida’)
17.13.1.4 Octobrachia (= Octopodiformes)
17.13.1.5 Giant Squid and Octopuses