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 remain 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 J . 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, a). Though at other times, 

 as Dr. Gros says 2 : c Une certaine serie d'Euglenes se 

 decolourait entierement, comme a Pordinaire et donnait 



1 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 Euglenze which became transformed into Rotifers, Nematoids, and 

 Tardigrades : ' Ce rebus de substance s'est prdsente presque constam- 

 ment cette annee, tandis que, 1'ann^e dernikre, 1'Euglkne se transformait 

 de toutes pieces.' 



2 Loc. cit, p. 475. 



