Multiplication, 57.--Spontaneous generation, 58.--Simplest multiplication and development, 59.--Birth and hatching, 61.--Life-history, 62. PART II SYSTEMATIC ZOOLOGY XIV.--THE CLASSIFICATION OF ANIMALS. [Laboratory exercise and recitation], 65.--Basis and significance of classification, 65.--Importance of development in determining classification, 67.--Scientific names, 68.--An example of classification, 68.--Species, 69.--Genus, 70.--Family, 72.--Order, 72.--Class and branch, 73. XV.--BRANCH PROTOZOA: THE ONE-CELLED ANIMALS. EXAMPLE: THE BELL ANIMALCULE (VORTICELLA SP.) [Laboratory exercise], 75. OTHER PROTOZOA. Form of body, 78.--Marine Protozoa, 80. XVI.--BRANCH PORIFERA: THE SPONGES. EXAMPLE: THE FRESH-WATER SPONGE (SPONGILLA SP.) [Laboratory exercise], 84. EXAMPLE: A CALCAREOUS OCEAN-SPONGE (GRANTIA SP.) [Laboratory exercise], 85. EXAMPLE: A COMMERCIAL SPONGE [Laboratory exercise], 86. OTHER SPONGES. Form and size, 87.--Skeleton, 88.--Structure of body, 88.--Feeding habits, 88.--Development and life-history, 89.--The sponges of commerce, 90.--Classification, 91. XVII.--BRANCH CŒLENTERATA: THE POLYPS, SEA-ANEMONES, CORALS, AND JELLYFISHES. POLYPS, SEA-ANEMONES, CORALS, AND JELLYFISHES. General form and organization of body, 93.--Structure, 94.--Skeleton, 95.--Development and life-history, 95.--Classification, 96.--The polyps, colonial jellyfishes, etc. (Hydrozoa), 97.--The large jellyfishes, etc. (Scyphozoa), 101.--The sea-anemones and corals (Actinozoa), 102.--The Ctenophora, 107. XVIII.--BRANCH ECHINODERMATA: THE STARFISHES, SEA-URCHINS, SEA CUCUMBERS, ETC. EXAMPLE: STARFISH (ASTERIAS SP.) [Laboratory exercise].--External structure, 108.--Internal structure, 110.--Life-history and habits, 113. EXAMPLE: SEA-URCHIN (STRONGYLOCENTRUS SP.) [Laboratory exercise].--External structure, 113. OTHER STARFISHES, SEA-URCHINS, SEA CUCUMBERS, ETC. Shape and organization of body, 116.--Structure and organs, 117.--Development and life-history, 119.--Classification, 120.--Starfishes (Asteroidea), 121.--Brittle stars (Ophiuroidea), 122.--Sea-urchins (Echinoidea), 123.--Sea-cucumbers (Holothuroidea), 124.--Feather-stars (Crinoidea), 125. XIX.--BRANCH VERMES: THE WORMS. EXAMPLE: THE EARTHWORM (LUMBRICUS SP.) [Laboratory exercise].--External structure, 127.--Internal structure, 129.--Life-history and habits, 133. OTHER WORMS. Classification, 135.--Earthworms and leeches (Oligochætæ), 136.--Flat worms (Platyhelminthes). 137.--Round worms (Nemathelminthes), 140.--Wheel-animalcules (Rotifera), 142. XX.--BRANCH ARTHROPODA: THE CRUSTACEANS, CENTIPEDS, INSECTS, AND SPIDERS. CLASS CRUSTACEA: CRAYFISHES, CRABS, LOBSTERS, ETC.