CONTENTS 



PART I 



PRELIMINARY CHAPTERS 

 THE EXTERNAL PARASITES 



CHAPTER I 



PAPE 



Introduction 1 



Origin of parasitism; Influences inhibiting organic multiplication; The 

 struggle for existence; The sheltered mode of life; Its effect; Phases of the 

 symbiotic relationship; Example of mutualism; Examples of commensalism ; 

 True parasitism; Adaptive and degenerative modifications of the parasite; 

 Faculties of parasitic and predatory animals compared; Simplicity, primitive 

 and degnerative; The Tunicata; Functions involved in adaptation to para- 

 sitism; The reproductive process in MeJophagus ovinus; Development oi the 

 reproductive function in parasites; Parasitism of Gaslrophilus inteslinalis; 

 Alternation of hosts in life cycle of parasites; The complicated cycle of the 

 liver fluke; The tapeworm as an example of extreme parasitism; Deductions 

 as to the systematic position of parasites through comparison with free-living 

 forms. 



CHAPTER II 



Forms of Parasitism and Influence upon the Host 7 



Terms used in parasitology; Symbiosis; Mutualism; Commensalism; 

 Helotism; Parasitism; Phytoparasites; Zooparasites; Optional occasional 

 parasites; Obligate occasional parasites; Determinate transitory parasites; 

 Permanent parasites; Fixed parasites; Erratic parasites; Determinate 

 erratic parasites; Monoxenous parasites; Heteroxenous parasites; Trans- 

 migration; Incidental or stray parasites; Ectoparasites; Entoparasites; 

 Helminthes; Terms used in the designation of parasitic diseases; Preda- 

 cious and parasitic animals; Factors governing injuiy to the host by para- 

 sites; General etiologic factors. 



CILIPTER III 



Phulum I. Arthropoda 13 



Characteristics of the Arthi'opoda; Characteristics of the class Insecta; 

 Insect methods of reproduction; Duration of life of insects. 



