UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



ZOOLOGY 



Vol. 19, No. 4, pp. 135-190, plates 2-6, 3 figures in text October 4, 1919 



A COMPARISON OF THE LIFE CYCLE OF 



CRITHIDIA WITH THAT OF TRYPANO- 



SOMA IN THE INVERTEBRATE 



HOST 



BY 



IRENE McCULLOCH 



CONTENTS 



PAGE 



Introduction 136 



Historical summary 139 



The comparative morphology of Crithidia and the crithidial stages of 



Trypanosoma 144 



Nucleus 146 



Blepharoplast 147 



Parabasal body and rhizoplasts 149 



Flagellum and undulating membrane 151 



The life cycle of Crithidia euryophthalmi 152 



The developmental series 153 



Stomach phase 153 



Extracellular crithidias 154 



Oval spores 154 



Developing crithidias 154 



Multiple fission 155 



Endogenous budding 155 



Somatella 162 



Binary fission 165 



Intracellular crithidias 168 



Rectal phase 170 



Nectomonads 171 



Haptomonads 174 



Final spore forms 176 



The degenerative series 177 



Conclusions 178 



Literature cited 180 



Explanation of plates 182 



