THE BEGINNINGS OF IIFE. 479 



jection similar to that which I have described in con- 

 nection with Trichomonas ^ — a projection whose volume 

 increases, in proportion as the substance on the corre- 

 sponding part of the inner wall of the cell diminishes. 

 All pass through numerous transformations before 

 attaining their final form, though all do not attain this 

 form. Some become the prey of other Infusoria • some, 

 arrested in their development^ owing to causes which 

 remain hidden, return to their primitive form — that 

 of the Amoeba.' 



Again, after what has already been' stated, it becomes 

 more easy for us to accept the fact that the Ciliated 

 Infusorium named Otostoma by Mr. Carter, may arise 

 within the closed internodes of Nitella, in the manner 

 which he originally described. 



The following observations were repeated by Mr. 

 Carter on several occasions. He says: — ^ About three 

 weeks after gathering plants of Nitella and placing 

 them in a basin of water, the green layer of the long 

 slender internodes becomes separated from the cell wall, 

 and gathered up into dark, spherical bodies, averaging 

 about the 100th part of an inch in diameter, or large 

 enough to be seen by the unassisted eye .... These at 

 first move up and down the internode with the rapidity 

 of animalcules, but afterwards lose this power of locomo- 

 tion and become stationary. They then present, under 



and thirty-seven specimens of the common Rotifer — two-thirds of which 

 had been produced by reproduction.' 

 1 See p. 384. 



