viii CONTENTS 



CHAPTER PAGE 



General Consideration of the Coelenterates — Distribution — Anatomy — 

 Physiology — Habitat — Regeneration — Fossil Relatives — Ancestry and 

 Relationship to Other Phyla — Economic Importance of Coelenterates. 



V — ^Platyhelminthes 71 



Classification — Characteristics — Natural History — Class i. Turbella- 

 ria — Type of Group — Planaria — Class 2. Trematoda — Anatomy and 

 Life History of the Liver Fluke — Trematode Parasites — Class 3. Ces- 

 toda — Type of Group — Taenia solium — Cestode Parasites — General 

 Consideration of the Platyhelminthes — Distribution — Anatomy and 

 Physiology — Behavior — Regeneration — Fossil Relatives — Ancestry 

 and Relationship to Other Phyla — Axial Gradient Theory of Child — 

 Nemertinea, Possibly Allied to Platyhelminthes. 



VI — Nemathelminthes 87 



Classification — Characteristics — Natural History — Class Nematoda — 

 Family i. Ascaridae — Tvpe of Group — Ascaris lumbricoides — Family 

 2. Anguillidae — Life History of Caconema (Heterodera) radicicola — 

 Family 3. Strongylidae — Life History of Necator americana — Family 

 4. Trichotrachellidae— Family 5. Filarldae — Life History of Filaria 

 bancrofti — Family 6. Trichinellidae — Life History of Trichinella 

 spiralis — Uncertain Classes formerly placed under Nemathelminthes — 

 Acanthocephala — Gordiaceae — Mermithidae — General Consideration 

 of the Nemathelminthes — Distribution — Physiology — Fossil Relatives 

 — Ancestry and Relationship to Other Phyla. 



VII— Annelida 100 



Classification — Characteristics — Natural History — Class i. Archi- 

 Annelida — Polygordius — Class 2. Chaetopoda — Type of Group — 

 Lumbricus terrestris — Conjugation in the Earthworm. Class 3. 

 Hirudinea — Type of Group — Hirudo medicinalis — Adaptation of the 

 Leech to its Mode of Life — General Consideration of the Annelida — 

 Distribution and Habits— Parasites of the Annelida — Physiology, 

 Anatomy, and Locomotion — Regeneration — Fossil Relatives — Ances- 

 try and Relationship to Other Phyla — Economic Importance of An- 

 nelida. 



VIII — Trochelminthes • . • • 121 



IX MOLLUSCOIDEA I 27 



Natural History— Class i. Brachiopoda— Class 2. Bryozoa (Polyzoa) 

 — Class 3. Phoronidea. 



X ECHINODERMATA 1^9 



Classification — Characteristics — Natural History — Class i. Aste- 

 roidea — Type of Group — Asterias — Artificial Parthenogenesis — Class 

 2. Ophiuroidea — Class 3. Echinoidea — Class 4. Holothuroidea — 

 General Considerations — Anatomy and Locomotion — Physiology — 

 Behavior — Embryonic Development — Parental Care — Regeneration 



