XViii , TABLE OF CONTENTS. 



CHAPTER XVI. 



PAGE 



UNSEGMENTED WORMS l86 



Time. 1-4 periods. 



CHAPTER XVII. 



ANNULATA J 95 



Time. 2-4 periods. 



CHAPTER XVIII. 



ECHINODERMATA 2 6 



Time. 1-3 periods. 



CHAPTER XIX. 



MOLLUSCA 2I 5 



Time. 2-5 periods. 



CHAPTER XX. 



\ ARTHROPODA 232 



Time. 10-15 periods. 



CHAPTER XXI. 



CHORDATA 274 



Time. 2-10 periods. 



CHAPTERS XXII. 



CLASS FISHES 281 



Time. 2-3 periods. 



CHAPTER XXIII. 



CLASS AMPHIBIA 296 



Time. 1-2 periods. 



CHAPTER XXIV. 



CLASS REPTILES 306 



Time. 1-2 periods. 



CHAPTER XXV. 



CLASS AVES (BIRDS) 317 



Time. 3-5 periods. 



