EXPLANATION OF PLATES 



The drawings have all been outlined with the aid of a camera lucida, using a 

 Spencer 1 .8 mm, oil-immersion objective and a Zeiss no. 12 compensating ocular. 

 The draw-tube was set to make a magnification of 4000 at the level of the table 

 where the tracing was done. In reproduction the magnification has been reduced 

 to 3000. Details of structure were completed with ink while the object remained 

 under observation, then each drawing has been checked two or three times by 

 subsequent comparison with the object. All figures from material stained with 

 iron-alum haematoxylin. Fixation will be indicated for each figure. For these 

 fixing fluids the following abbreviations will be used: Allen's for Allen's 'B-15,' 

 Carn. for Carnoy's fluid, Schaud. for Schaudinn's fluid, sub.-acet. for sublimate- 

 acetic, and wk. Flem. for the weaker fluid of Flemming. 



PLATE 1 



EXPLAXATION OF FIGURES 



1 to 3 Vegetative individuals showing some diff'erences due to use of different 

 fixatives; fig. 1, Carn., chromatic basal rod not stained; fig. 2, sub.-acet., vacuole 

 contents stained ; fig. 3, wk. Flem., parabasal body stained. 



4 to 6 Wk. Flem., parabasal body stained, constricted in figs. 4 and 5, under- 

 going change in fig. 6. 



7 to 9 Schaud., vegetative individuals; fig. 7, view frorri left side; fig. S, possi- 

 ble division of rows of chromatic granules; fig. 9, hypertrophied (abnormal ?) 

 nucleus. 



148 



