TABLE OF CONTENTS 



PAGES 



Introduction 7 



Material and Methods ". 10 



Observations on Carditis robustus 16 



Determination of Species 16 



Habits of Adults 19 



Early Development 21 



Parasitism 23 



Organogeny 29 



Metamorphosis 29 



Derivation of Tissues 29 



Later Development 31 



Observations on Paragordius varius 44 



Determination of Species 44 



Habits of Adults 44 



Early Development 45 



Parasitism 45 



Organogeny 47 



Discussion 56 



Biology 56 



Occurrence and Behavior of Adults 56 



Behavior of Larvae 59 



Infection and Intermediate Host 59 



Developmental Period 60 



Organogeny 60 



Metamorphosis 61 



Later Development 62 



Physiology 68 



Nutrition 68 



Excretion 68 



Functions of Nervous System 69 



Relationships 70 



Bibliography 72 



Explanation of Plates 76 



