Contents 13 



Page 

 333; Mcrychippus, 333; Pliohippus, 333; Eqims, 333; Some Special Aspects 

 of Evolution, 335 ; Convergence, 335 ; Mimicry and Protective Coloration, 

 336; The Distribution of Animals, 337; Migration, 337; Barriers, 337; 

 Isolation, 338; Wallace's Zoogeographic Regions, 340; The Geological 

 Time Scale, 341. 



SECTION IV 

 THE ANIMAL KINGDOM 



CHAPTER 19 



THE ANIMAL KINGDOM 344 



Cellular Organization, 344 ; Symmetry, 345 ; Germ Layers, 345 ; Presence 

 of a Body Cavity, 345 ; Metamerism, 346 ; Organ Systems, 346 ; The Princi- 

 pal Divisions of the Animal Kingdom, 346. 



CHAPTER 20 



THE PHYLUM PROTOZOA ...._. 349 



Characteristics of the Phylum, 350 ; Importance of the Protozoans, 352 ; 

 The Classes of Protozoans, 352 ; The Class Flagellata, 353 ; Euglcna, 353 ; 

 Volvox, 355 ; Other Colonial Flagellates, 356 ; Other Phytomastigina, 356 ; 

 The Zoomastigina, 357; The Class Sarcodina, 359; Amoeba proteus, 359; 

 Other Sarcodina, 361 ; Parasitic Sarcodina, 362 ; The Class Sporozoa, 363 ; 

 The Coccidians, 363 ; The Haemosporidians, 365 ; The Class Ciliata, 367 ; 

 Paramecium, 368; Binary Fission, 369; Autogamy, 370; Conjugation, 370; 

 Cytoplasmic Inheritance, 372 ; Other Free-Living Ciliates, 372 ; Parasitic 

 Forms, 373 ; The Class Suctoria, 373. 



CHAPTER 21 



SOME OF THE LOWER METAZOANS 375 



The Phylum Porifera, 375 ; Characteristics of the Phylum, 376 ; The Ar- 

 rangement of the Canal Systems, 377; Life History. 379; The Biology 

 of the Sponges, 380 ; Economic Importance, 381 ; The Classes of Sponges, 

 381; The Phylum Mesozoa, 382; The Phylum Coelenterata, 383; Char- 

 acteristics of the Phylum, 383 ; The Classes of Coelenterates, 385 ; The Class 

 Hydrozoa, 386 ; Hydra, 386 ; External Anatomy, 386 ; Microscopic Anat- 

 omy, 387; Reproduction, 388; The Responses of Hydra to Its Environ- 

 ment, 389; Regeneration. 390; Other Hydrozoans, 391; Obelia, 391; 

 Gonioncmus, 393; The Siphonophores, 393; The Class Scyphozoa. 393; 

 Aurellia, 394; The Class Anthozoa, 395; Metridium, 396; The Corals, 

 397; The Phvlum Ctenophora, 397; Characteristics of the Phylum, 398; 

 The Classes of Ctenophores, 399; The Class Tentaculata, 399. 



CHAPTER 22 



THE PHYLA PLATYHELMINTHES AND NEMERTINA 401 



The Characteristics of the Phylum, 402 ; The Classes of Platyhelminthes, 

 404 ; The Class Turbellaria, 404 ; The Anatomy of Planaria, 404 ; The Be- 

 havior of Planaria, 407; Regeneration, 408; Other Turbellanans, 409; The 

 Class Trematoda. 409: The Life History of the Sheep Liver Fluke, 409; 

 The Anatomy of Opisthorchis sinensis, 411 ; The Life Cycle oiOpishorcJus 

 sinensis, 413; Other Parasitic Flukes, 414; The Class Cestoda, 416; The 

 Anatomy of an Adult Tapeworm, 416; The Life Cycle of Tacma sohum, 

 418; Other Important Tapeworms. 418; Adaptations to Parasitic Lite, 

 420; The Phylum Nemertina, 421 ; The Characteristics of the Phylum, 421. 



