THE BEGINNINGS OF LIFE. 197 



interior, as well as the so-called vacuoles the latter, 

 which constantly change in size and in situation, being 

 usually filled with fluid contents l . 



Another most interesting mode of development of 

 reproductive germs occurring in the higher nucleated 

 forms of Amoebae the Protoplasta of Prof. Haeckel 

 has been described by Nicolet 2 . In these higher Amcebse, 

 which, though they continually change their form, do not 

 send out complicated processes like those of the Proto- 

 myxa, multiplication takes place by means of fission and 

 also by germ-formation. The process of germ-forma- 

 tion closely resembling that by which the spores are 

 produced in Conferva area only takes place towards 

 the close of the life of the parent Amoeba, whose exist- 

 ence is terminated by the setting free of its numerous 

 progeny. At a certain stage in the life of one of these 

 individuals such as would have been named Amoeba 

 princeps by Ehrenberg the granules contained in the 



1 Although a Protomyxa is capable of increasing much in size and 

 complexity by the ordinary processes of growth, there is also another 

 process by means of which the larger individuals are produced. Pro- 

 fessor Haeckel says, ' I could many times immediately follow in the 

 swarms of Protomyxa under my eyes the formation of a plasmodium by 

 the growing together (concrescence) of two or more Amoebae.' Some- 

 times it happened that two Amoebae, attaching themselves to a single 

 Navicula, would, by drawing themselves over it, meet in the middle 

 and then become united to one another. After the process of digestion, 

 the united plasma-mass would free itself from the silicious diatom shell, 

 but would remain as a single individual. To such fusions of originally 

 distinct living things we shall have again to refer. 



2 Thompson's Arcana Naturae, 1859 (Paris), p. 27. 



