CONTENTS 



CHAPTER XV. THE SPONGES, Subkingdom Porifera. 



Distinctive Characteristics of the Group Reproduction The Calcareous Sponges (Class 

 Calcared) Six-Rayed or Glass-Sponges (Class Hexactinellida} The Common 

 Sponges (Class Demospongia} Four-Rayed Sponges (Order Tetractinellida} 

 The Fleshy Sponges (Order Carnosa) Single-Rayed Sponges (Order Monaxonida) 

 Fresh- Water Sponges Horny Sponges (Order Cerafosa), 



CHAPTER XVI. THE LOWEST ANIMALS, Subkingdom Protozoa. 



Characteristics of Protozoans The Root-Footed Group (Class Rhizopoda) The Amcebas 

 (Order Lobosa) Order Foraminifera Sun Animalcules (Order Heliozoa} Order 

 Radiolaria The Infusorial Animalcules (Class Infusoria) Flagellated Infuso- 

 rians (Order Flagellata} Ciliated Infusoria (Order Cilia/a), 



INDEX 



IX 



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3525 



3545 



