CONTENTS 
HALF-VOL. VII 
NERVOUS SYSTEM AND SENSE-ORGANS 
CHAPTER LVII.—GENERAL PRINCIPLES—NERVOUS SYSTEMS 
OF BACKBONELESS ANIMALS (INVERTEBRATA) AND BACK- 
BONED ANIMALS (VERTEBRATA) 
GENERAL PRINCIPLES—Properties of Protoplasm: Sensitiveness and Spontaneity. 
Stimuli: Reaction of Protozoa to Stimuli 
NERVOUS SYSTEMS OF BACKBONELESS ANIMALS 
(INVERTEBRATA) 
Division of Labour in Cell-Communities 
NERVOUS SYSTEMS OF ZOOPHYTES (CCELENTERATA)—Ectoderm and Endoderm: 
Nerve-Cells and Nerve-Fibres, Neurons; Sea-Anemones; Jelly-Fishes - 
NERVOUS SYSTEMS OF SEGMENTED WORMS (ANNELIDA)—Nerve-Ring and 
Nerve-Cord in Earth-Worm, &c.; Head and Brain; Reflex Action; Visceral 
Nervous System; Comparison with Vemertine Worms (Nemertea) 
NERVOUS SYSTEMS OF JOINTED-LIMBED INVERTEBRATES (ARTHROPODA)— 
Comparison with Annelids - 
Nervous Systems of Crustaceans (Crustacea)—Apus, Crayfish, and Crab - 
Nervous Systems of Atr-breathing Arthropods (Tracheata)—Peripatus, 
Centipedes and Millipedes, Scorpions and Spiders, Insects - 
NERVOUS SYSTEMS OF MOLLUSCS (MOLLUSCA)—Mail-Shells (CAz#on), Snails and 
Slugs (Gastropoda), Bivalves (Lamellibranchia), Tusk-Shells (Scaphopoda), 
Head-footed Molluscs (Cephalopoda) ° - - - 
NERVOUS SYSTEMS OF BACKBONED ANIMALS (VERTEBRATA) 
Brain, Spinal Cord, Sympathetic Nervous System, Spinal Nerves, Cranial Nerves ; 
Development of Nervous System - 
THE BRAIN OF VERTEBRATES—Development and Structure; Increase of Com- 
plexity in ascending the Scale - 
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