20 



THE STRUCTURE AND LIFE 



F 'g- J 3- 



? 



7n 



A c 



Fig. 14 



it moves about in the maceration, often drawing in its train the two small 

 valves of the diatom which has given it birth. The outside covering of 

 these newly-born, large-sized Nitzschia is very soon charged with silica and 

 covered with the striae and carinate puncta which characterise this species ; 

 lastly, the form of this more or less abnormal species is determined by its 

 forming increasingly rectilinear septa and by bipartition (fig. 14). 



" In a cultivation which is 10 c.c. (2.81525 fl. drachms) in volume many 

 millions of cells similar to those just mentioned may often be counted. 



"In short, the re-establishment of the maximum form of diatoms is 



