PART ONE： SOME BASIC CONCEPTS 1
1．ZOOLOGY，THE SCIENCE OF ANIMAL LIFE 2
2．CHEMICAL LEVELS OF ORGANIZATION 11
3．LIVING LEVELS OF ORGANIZATION 23
PART TWO： PRIMITIVE FORMS OF ANIMAL LIFE 41
4．PROTOZOA 42
5．SPONGES 75
6．COELENTERATES 82
7．CTENOPHORES 115
PART THREE： THE STREAM OF LIFE 123
8．DEVELOPMENT 124
9．GENETICS 147
10．EVOLUTION 182
PART FOUR： THE PROTOSTOME BRANCH OF THE ANIMAL KINGDOM 225
11．FLATWORMS 226
12．NEMATODES AND OTHER ASCHELMINTHES 250
13．MINOR PROTOSTOMES 266
14．ANNELIDS 272
15．MOLLUSKS 295
16．SPIDERS，TICKS AND OTHER CHELICERATE ARTHROPODS 313
17．CRUSTACEANS，INSECTS，AND OTHER MANDIBULATE ARTHROPODS 331
PART FIVE： THE DEUTEROSTOME BRANCH OF THE ANIMAL KINGDOM 369
18．ECHINODERMS 370
19．PROCHORDATES 387
20．FISHES 399
21．AMPHIBIANS 425
22．REPTILES 452
23．BIRDS 469
24．MAMMALS 492
PART SIX： ANIMALS AND THEIR WORLD 559
25．ANIMAL BEHAVIOR 560
26．ECOLOGY 585
GLOSSARY OF BIOLOGICAL TERMS 605
INDEX 617