in Eudorina elegans and Cryptoglena. 245 



mulberry shape (figs. 16, 17). How long it remains in the " still" 

 form I am ignorant ; but having only seen it in the active state 

 during the months of May, June and August, and throughout the 

 rest of the year in the "still" one, I am inclined to think that it 

 only comes into the active state during the summer months, 

 and then for the purpose of fecundation. 



Does not the disappearance of the eye-spot in the "still" 

 form thus seem to point out its analogy with the bright colours, 

 especially the red, presented by plants in their flowers during 

 the season of fecundation, rather than with the eye of animals ? 



In several instances, also, where I have found this Chlamydo- 

 coccus with Eudorina, they have been accompanied by long 

 Closteriform cells. It was the case in that above mentioned, 

 where the latter was undergoing impregnation. Some of these 

 have an eye-spot, which, with the nature, arrangement, and 

 general aspect of their internal contents, show that they belong 

 to the class of organisms with which they are associated. Their 

 cell-wall also is more or less plastic, or was so when they were 

 assuming this spicular form ; for many have one or more diver- 

 ticula extending from them, some are bifid, and a few irregularly 

 stellate. What they are, I know not ; but Dr. Cohn has figured 

 the same kind of cells, in company with Sphceroplea annulina, 

 under impregnation*. 



Trachclomonas, Ehr., also appears to me to undergo multi- 

 plication in a similar way to Eudorina and Chlamydococcus ; for 

 I have often seen the largest Trachelomonad of a pool divided 

 up into a group of apparently sixteen cells within the lorica; 

 and this may account for the myriads of three to four smaller 

 sizes that are frequently found together in this way. The latter 

 certainly appear in a green form first, that is, without the lorica, 

 which gradually becomes supplied afterwards. Thus, impreg- 

 nation also in the Trachelomonads may take place like that 

 already mentioned in Eudorina, after the parent-cell has under- 

 gone division within the lorica. At first I thought that the first 

 form of Eudorina arose in this way, and that when the division 

 of the Trachelomonad arrived at sixteen, the lorica burst, and 

 thus liberated a Eudorina ; also that the cells into which the 

 Eudorina ultimately divides formed the small Trachelomonads ; 

 but in the pools where I found the Eudorina undergoing im- 

 pregnation there was not a single Trachelomonad, so that this 

 theory does not hold good. 



How Euglena viridis and the Euglena generally become im- 

 pregnated, I have no conception. There is no doubt that E. vi- 

 ridis becomes distended with the cells which I have heretofore 



* Ann. des Sc. Nat. t. v. pi. 12. fig, 3. Bot. 1856. 



