CONTENTS 13 



CHAPTER XII 



PAGE 



Genetics and Eugenics (By Frank G. Brooks) _____i___ 235 

 The History of a Great Discovery, 235; Mendel's Law, 235; Deriva- 

 tives of Mendel's Law, 237; The Physical Basis, 238; Plotting Crosses, 

 239 ; Complications of Mendelian Inheritance, 241 ; Inheritance of Sex, 

 245; Linkage, 246; Sex Linkage, 246; Crossing Over, 248; Mutations, 

 249; Human Heredity, 249; Matings Among Defectives, 252; The 

 Differential Birth Rate, 253; Family Size in Eugenic Groups, 253; 

 Family Size in Dysgenic Groups, 255; What Can Be Done? 256; 

 Some Eugenic Measures, 256. 



CHAPTER XIII 



Classification of Animals ______________ 259 



Rules of Nomenclature, 260 ; Summary of the Classification of Animals, 

 261; Phylum I. Protozoa, 261; Phylum II. Porifera, 262; Phylum 

 III. Coelenterata, 262; Phylum IV. Ctenophora, 263; Phylum V. 

 Platvhelminthes, 263; Phvlum VI. Nemathelminthes, 263; Phvlum 

 VII. Annelida, 263; Phylum VIII. Echinodermata, 264; Phylum 

 IX. Mollusca, 264; Phylum X. Arthropoda, 264; Groups of Non- 

 chordates Whose Systematic Position Is Uncertain, 265; Phylum 

 XI. Chordata, 266. 



CHAPTER XIV 



Protozoa in General ________________ 268 



Characteristics, 268; Classification, 268; Colonial Protozoa, 277; 

 Tropisms and Animal Reaction, 278; Economic Relations of Protozoa, 

 279. 



CHAPTER XV 



Representative Protozoa — Euglena, Amoeba and Paramecium _ _ _ 282 

 Euglena, of Class Mastigophora, 282; Habitat and Characteristics, 

 282; Structure, 282; Food and Assimilation, 283; Respiration and 

 Excretion, 284; Reproduction and "Life Cycle, 284; Behavior, 285; 

 Locomotion and Flagellar Movement, 285; Amoeba, of Class Sar- 

 codina, 285; Characteristics and Habitat, 286; Structure, 286; Metab- 

 olism, 287; Reproduction and Life Cycle, 289; Behavior, 291; 

 Amoeboid Movement and Locomotion, 292; Paramecium, of Class In- 

 fusoria, 293 ; Characteristics and Habitat, 293 ; Structure, 293 ; Metab- 

 olism, 295; Reproduction and Life History, 296; Behavior, 299; 

 Locomotion, 302. 



CHAPTER XVI 



Hydra, of Phylum Coelenterata ____________ 303 



Classification of the Phylum, 304; Habitat and Behavior of Hydra, 



