526 THE BEGINNINGS OF LIFE. 



These metamorphoses, taking place as they do in 

 masses of matter ^i^" or more in diameter, can be 

 followed with the greatest ease ; and, moreover, certain 

 features are frequently presented which preclude all 

 possibility of mistake with regard to the identity of the 

 bodies undergoing transformation. Thus, it occasion- 

 ally happens that one or two portions of the Euglense 

 escape transformation, and rem.ain within the cyst by 

 the side of the embryo — ^just as portions of the em- 

 bryonal spheres of Nitella occasionally escape trans- 

 formation when these segment into Monads i. And at 

 other times, phenomena have been observed which are 

 still more capable of convincing even the most sceptical 

 of those who have not themselves witnessed such trans- 

 formations. Some of the encysted Euglense undergo 

 a process of fission, and whilst still enclosed within the 

 common cyst-like envelope, one of the bodies so pro- 

 duced may become rapidly decolourized and converted 

 into an embryo Nematoid, whilst the twin product 

 remains by its side as a still green or only very slightly 

 decolourized Euglena (Fig. 94, d). Though at other times, 

 as Dr. Gros says 2 : — <■ Une certaine serie d'Euglenes se 

 dccolourait entierement, comme a I'ordinaire et donnait 



^ See Fig. 79 c. At other times, however, the transformation into Monads 

 takes place without any remainders ; and so Dr. Gros says concerning these 

 large Euglen?e which became transformed into Rotifers, Nematoids, and 

 Tardigrades : — ' Ce rebus de substance s'est pr^sente presque constam- 

 ment cette annee, tandis que, I'annee dernibre, I'Eugl^ne se transformait 

 de toutes pieces.' 



^ Log. cit., p. 475. 



