fl-' 



'446 



THE BEGINNINGS OF IIFE. 



still presenting an embryonic appearance — in vessels 

 containing Euglen^ and Vaucheria. 



8. Transformation into Desmids and Fediastre£, The 



F 



t 



only Desmids that have been ascertained to be produced 

 by the transformation of entire Euglen^e, are those large 

 specimens belonging to the genus Closterium. Although 

 I have not myself had the satisfaction of witnessing this 

 transformation^ Dr. Gros states that he has observed it 

 on several occasions. The particular modification of 

 the Euglena which is occasionally apt to undergo this 

 change is^ however^ quite familiar to me. Specimens 

 are frequently to be observed which^ having lost their 

 flagellum^ are prone to assume an elongated worm-like 

 form. They crawly too^ in a slow worm-like manner, 

 rather than swim , and are always noticeable on account 

 of the extreme brilliancy of the well-formed green 

 vesicles which they contain, and of the bright carmine 

 colour of their so-called ^ eye-speck.' After a time, their 

 movements grow more and more languid^ and the 

 green vesicles separate from one another at the middle 

 of the body {e)^ so as to leave a clear space similar to 

 that which also exists to a certain extent in the various 

 forms of Closteria — into one or other of which these 

 languid and elongated Euglenx may, according to Dr. 

 Gros, be gradually transformed. The transformation 

 sometimes takes place in a few days, and sometimes 



w 



only after two or three weeks ^ whilst other specimens 



of the same kind 



of Euglen-cE 



may remain, even 



for 



months, without undergoing any noticeable alteration^ 





(liiiiin of Diatom! 



». Euglena in e 

 \ t. Two forms 



^'^' Chlamidomc 

 !• One of 



WOI 



gradualh 



Arthrod 

 Uv 



i 



^ See loc cit., p. 317. 



another 



^- O-ie of ij' 



Pinions 

 *aracte 



