456 THE BEGINNINGS OF II FE. 



into organisms of a more or less vegetal type, we have 

 now to refer to their metamorphoses into decidedly 

 animal forms of various grades of organization. Nothing 

 is more startling, and yet nothing more common, than 

 to see neighbouring specimens of the same stock of 

 Euglen^, without any appreciable cause, turning along 

 totally different lines of development. As Dr. Gros 

 pointed out, ^suivant des circonstances souvent inap- 

 preciables, on volt une vesicule suivre un developpe- 

 ment animal, tandis que sa congenere et jumelle suit 

 un rhythme vegetal.^ He also adds : — ' Les circon- 

 stances de chaleur, de saison, de lumiere, de quantite 

 et de qualite de matiere, le plus souvent imponderables, 

 donnent lieu a des caprices de reproduction, si I'on 

 osait appeller caprices ce qui ne tient, qu'a I'insufficance 

 de nos moyens d'observation.' 



10. Transformation Into Actinopkrys or AmcebiC^ luhich 

 subsequently become converted Into various forms of Ciliated 

 Infusoria. The Actinophrys and the Amoeba are regarded 

 by Dr. Gros ^ as mere intermediate modes of existence 

 into which Euglense are apt to lapse when the conditions 

 operating upon them are not favourable to their more 

 direct transformation into higher forms. 



1 have several times had the opportunity of watching 

 the different stages through which Euglense pass during 

 their transformation into Amocbie. It most frequently 

 occurred in this manner : — The Euglena became motion- 

 less and somewhat irregular in shape, whilst its chioro- 

 ^ See loc. cit., p. 330. 



