CONTENTS 



CHAP. PAGE 



I. THE ANIMAL KINGDOM. Introductory outline of 



the Animal Phyla. Antiquity of the Phyla . 1 



II. THE SIMPLEST ANIMALS AND PLANTS AND THE 



ORIGIN OF LIFE. Plant and Animal nutrition. 

 Dependence of Animals on Plants. The role of 

 Bacteria. Protozoa. The Flagellata. Origin of 

 Life 20 



III. THE APPENDICULATE PHYLUM. Organization of 



an Annelid. Peripatus and the connection 

 between Annelids and Arthropods. The groups 

 of Arthropods. Arachnids. Limulus. Crus- 

 tacea. Nebalia and Anaspides .... 34 



IV. EMBRYONIC AND LARVAL HISTORIES. The theory 



of recapitulation. The Rhizocephala. Nauplius 

 larvae. Zoaea larva. Mysis larva. Trochosphere 

 and Auricularia larvae. Vertebrate embryology 58 



V. THE ANCESTRY OF THE VERTEBRATES. Chordate 

 characteristics. Ascidians. Amphioxus. The 

 Annelid theory of Vertebrate descent. Difficul- 

 ties of the theory. Balanoglossus and the 

 Echinoderms. Brachiopods. Lingula . . 75 



