PLATE I. 



The following abbreviations retain the same significance throughout the present and 

 succeeding Plates : — 



«. Nucleus or endoplast. 

 cv. Contractile vesicle. 

 /. Flagellum. 



cl. Collar. 

 0. Oral aperture. 

 an. Anal aperture. 



Where the figures are borrowed from another authority, the name of such authority is 

 bracketed ; where no bracketed name appears the figures are derived from the author's 

 original investigation. 



