THE BEGINNINGS OF LIFE. 467 



variation \ It will be well, however, to show a little 

 more fully that Ciliated Infusoria agree in both these 

 respects with what has been already established^ for 

 Fungus-germs, Monads, Amoebse, and other closely 

 related forms of life — of which, indeed, the former are 

 only more highly developed representatives. 



Much evidence exists tending to show that green 

 vegetal vesicles, whether derived from Mosses or from 

 any of the multitudinous forms of Alg£e_, may at times 

 undergo transformative changes closely corresponding 

 to those which Euglense of a similar size are apt to 

 pass through. Thus, although I have never seen en- 

 cysted specimens of the latter organisms converted into 

 Oxytricha or Plsesconia, I have many times seen both 

 these forms of Ciliata arise from large vesicles of 

 Chlorococcus. This form of Alga generally consists of 

 rather small corpuscles (from toVo" to -sinro" ii^ diameter) 

 which multiply in a pellucid jelly; but, especially when 

 growing near the surface of the water, some of its 

 vesicles are very prone to continue increasing in size^ 

 owing to a cessation of the process of fission. They 

 thus give rise to separate vesicles varying in size from 

 ToVo" to ^\-^' in diameter, and composed of small, 

 bright-green, chlorophyll corpuscles densely packed within 



^ As a rule, it may be said that those which arise from an encysted 

 mass of transforming matter begin their existence with more perfe 

 forms than those which proceed from the molecular transformations 

 non-encysted masses of protoplasm. 



2 In Chaps, xvii. and xx. 



H h 2 



