216 J. McA. KATER. 



Surrounding the nucleus is an area of very granular, slightly 

 chromatic cytoplasm. This is of very variable extensiveness, 

 sometimes filling half of the cell, while in others it is hardly 

 noticeable. 



Examination of living specimens reveals longitudinal striations 

 which number about eighteen. It was not possible to make sure 

 of the exact number and consequently their constancy could not 

 be determined. Superficial examination would lead one to think 

 that these were on the outside of the pellicle, but careful focusing 

 shows that they are slightly below the surface and that they do 

 not quite reach either the anterior or posterior ends. They, 

 consequently, must be either on the inside of the pellicle or in the 

 outermost layer of the ectoplasm. After devoting considerable 

 study to this question I rather lean towards the latter, and think 

 that the striated effect is produced by some stringy arrangement 

 of the protoplasm. Living mounts or iodine-eosin preparations 

 show this structure very well, but fixed and stained material gives 

 no indication of it. 



In the living cell all of the internal structure is effectually 

 screened by relatively large starch bodies which are located 

 peripherally. They may be so large and numerous that they are 

 packed closely together from one end to the other or they may be 

 entirely absent. By the use of a medium which does not contain 

 any carbohydrate (peptone 0.5 part, citric acid 0.2 part, mag- 

 nesium sulphate hydrate .02, KH 2 PO 4 .05 part, and water 100 

 parts) the organisms may be freed from starch for several days, 

 when it reappears again. No explanation of this fact is known. 

 The addition of cane-sugar to a timothy hay culture will increase 

 the amount of reserve starch in the cells. If they are only 

 partially filled with these bodies it is generally the posterior end 

 which is free from them. 



The following reactions are the justification for identifying this 

 material as starch ; it gives a deep blue color when treated with 

 iodine; it is digested by ptyalin; when treated with iodine and 

 heated it loses its color, the blue returning when cooled; when 

 treated with iodine followed by NaOH no color is found. 



The presence of a centriole could not be demonstrated in the 

 interkinetic cell of the active form. However it was seen in 



