448 THE BEGINNINGS OF LIFE. 



Although I have never seen the final stages of this 

 transformation., I had, even before becoming aware of 

 Dr. Gros' views, noticed the curious fact that very 

 small specimens of Closteria were never to be seen. 

 Wherever they are encountered one may see specimens 

 of different sizes and of different patterns, though with 

 the exception of those which, from their want of sym- 

 metry, are obviously the products of a recent fission 

 they are all large and more or less full-grown. So that, 

 just as in the case of the large Diatoms already alluded 

 to, their origin by metamorphosis is much more recon- 

 cilable with these facts than with the notion that they 

 are derived from small germs more especially since no 

 one has ever seen or knows anything about the mode of 

 production of such germs in Closterium 1 . Of course we 

 are far from implying that Closteria are only produced 

 from Euglense; since what is known concerning the 

 different modes of origin of other organisms might lead 

 us to expect that Closteria would also be derivable 

 from the transformation of other matrices, more or less 

 analogous to Euglense. 



Again, whilst the products of the third and subsequent 

 fissions of certain Euglense occasionally become con- 

 verted, in the manner described, into Diatoms, at other 

 times such products may be transformed into Pediastrese 

 belonging to the genera Micrasterias or Arthrodesmus. 

 Concerning the first kind of transformation (/), Dr. Gros 

 says: c Lorsque 1'utricule euglenien conservant ses 



1 See Pritchard's 'Infusoria,' 4th Ed., p. 12. 



