THE BEGINNINGS OF LIFE, 449 



vesicules parifissees adherentes entre elles^ va jusqu'a 

 la 3«5 4% 5^, 6« division ces vesicules s'arrangent sur 

 un meme plan , celles du contour poussent des cornes 

 et presentent les jolies formes des Micrasterias ^^ 

 Whilst the transformation into one or other of the 

 varieties of Arthrodesmus (^3 h) seems to occur still 

 more frequently. Dr. Gros writes : — ^ Les Arthrodesmus 

 qui ne sont que le 3^ degre de parifissure prenaient des 

 formes d'autant plus exigues que les utricules, d'ou ils 

 descendait, etaient plus petits^.' One of the con- 

 ditions under which Euglenas are prone to undergo 

 transformation into Pediastreae has also been definitely 

 ascertained. Dr. Gros observed that when Euglen^e 

 were sown upon a small patch of damp earth some of 

 them generally underwent this kind of metamorphosis_, 

 although others passed through different changes, so as 

 to become converted either into Diatoms or into the 

 organisms of which we are now about to speak ^. 



9. Transformation Into Conferva. Not only may the 

 ultimate products of repeated fissions of EugleniE be- 

 come converted into small Confervas, as we have already 

 stated (p. 443, note i); but occasionally an Euglena, 

 without such preliminary processes of fission, begins to 

 vegetate so as to produce a much larger Algal filament 



^ See loc. cit., p. 311, and PL K, fig. 25. 



2 PI. P, fig. 20-23. These transformations of Euglenge into different 

 kinds of Pediastreae are also referred to by Dr. Gros at pp. 303, 309, 318, 

 and 452. 



3 Seep. 453. 



VOL. II. G g 



