42 2 THE BEGINNINGS OF II FE. 



going change ^ Whilst Dr. Gros ^ has seen the contents 

 of each internode of an unnamed species of Conferva 

 separate from the walls and aggregate into a single 

 mass, which gradually assumed the form and charac- 

 teristics of a Euglena (Fig. 83). These somewhat 

 animalized organisms were subsequently liberated, owing 

 to the hyaline walls of the algoid compartments be- 

 coming thinner and thinner and ultimately rupturing. 



I have also seen remarkable changes of a similar kind 

 taking place within the small cells composing one of 

 the submerged leaves o^ a species of Potamogeton 3. 

 All the chlorophyll and protoplasm, in some of these 

 cells, became aggregated into a spherical mass ; whilst 

 other uninjured cells were seen, each of which con- 

 tained a large bright-green Euglena, having the usual 

 red pigment speck at one end. The bodies of these 

 creatures were as mobile as Amoebse, and they were 

 continually moving around within their narrow prisons. 

 They were also, in each case, the sole occupants of the 

 cell — the whole of the chlorophyll and protoplasm of 

 which had evidently been newly embodied into the 

 form of an Euglena. 



And lastly. Prof. A. M. Edwards is so certain about 

 the derivation of Euglenas from Confervas, that he says% 



^ See p. 392, and Fig. 77. 

 2 Loc. cit., p. 490, description of PI. K, fig. 9. 



' Heterogenetic changes take place quite freely within the cells of 

 almost all aquatic plants when they get into an unhealthy condition. 

 * ' Proceed, of Lyceum of Nat. Hist.,' New York, vol. i. (1871), p. 215. 



