CONTENTS. 



INTRODUCTION. 



PAGE 



DEFINITION OF THE SUBJECT i 



THE CELL i 



SOME DIFFERENCES BETWEEN ANIMALS AND PLANTS . . i 



CLASSIFICATION 2 



CHAPTER I. 

 BRANCH I. PROTOZOA 4 



CHAPTER II. 

 BRANCH II. SPONGES (PORIFERA) u 



CHAPTER III. 

 BRANCH III. JELLY-FISHES, ETC. (CCELENTERATA) . . .15 



CHAPTER IV. 

 BRANCH IV. CRINOIDS, STAR-FISHES, ETC. (ECHINODERMATA) 33 



CHAPTER V. 

 BRANCH V. WORMS (VERMES) 42 



CHAPTER VI. 

 BRANCH VI. SHELLS (MOLLUSCA) 51 



