CONTENTS 



PART I 



PRELIMINARY CHAPTERS 

 THE EXTERNAL PARASITES 



CHAPTER I 



PACE 



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 Melophagus ovinus; Development of the 

 reproductive function in parasites; Parasitism of Gastrophilus iniestincilis; 

 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 11 



FoEMS OF Parasitism and Inpitiencb upon the Host 7 



Terms used in parasitology; Symbiosis; Mutualism; Commensalism; 

 Helotism; Parasitism; Phytoparasites; ZoBparasites; 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; 

 Hehninthes; Terms used in the designation of parasitic diseases; Predar 

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

 sites; General etiologic factors. 



CHAPTER III 



Phulum I. Arthbopoda 13 



Characteristics of the Arthropoda; Characteristics of the class Insecta; 

 Insect methods of reproduction; Duration of life of insects. 



