THE STRUCTURE AND DEVELOPMENT OF A MYXO- 



SPORIDIAN PARASITE OF THE SQUETEAGUE, 



CYNOSCION REGALIS' 



H. S. DAVIS 



University of Florida 



SEVEN PLATES AND SEVEN TEXT-FIGURES 



I 



CONTENTS 



I . Introduction 333 



II. Material and metliods 334 



III. Description of trophozoites and sporulation 335 



1 . Disporoiis form 335 



a. Living trophozoites 335 



b. Preserved material 337 



2. Polysporous form 342 



a. Living trophozoites 342 



b. Preserved material 347 



IV. General discussion and review of literature 352 



1 . Polymorphism 352 



2. Multiplicative reproduction 353 



3. Propagative reproduction 355 



4. Mode of infection 359 



5. Fertilization 360 



V. Summary 362 



VI. Literature cited 363 



I. INTRODUCTION 



During the course of a somewhat extended study of the Myx- 

 osporidian parasites of the marine fishes of Beaufort, N. C, 

 an undescribed species was found in the urinary bladder and 

 ureters of the common squeteague, Cynoscion regahs, which 

 showed so many points of exceptional interest that an extended 

 investigation was made of its structure and development. 



1 Published with the permission of the Commissioner of Fisheries. Contri- 

 bution from United States Fisheries Biological Station, Beaufort, N. C. 



333 



