APPENDIX D. Ixix 



been seen more particularly on the bark of trees, and by 

 this means large green patches may be formed. 



5. ' But in some filaments there is a still more unsuspected 

 change, namely, in the production of cells of Gleocapsa. 

 The segmentation proceeds within the filament, as in the 

 instance just quoted ; but the divisions become invested in 

 a gelatinous envelope, while the parent cell-wall breaks up. 

 These Gleocapsa-like bodies then become free, and continue 

 the segmentation process as in Gleocapsa. This I have 

 shown in PI. LVIII. fig. iga. It is a condition by no 

 means rare in the winter months; considerable masses of 

 these bodies are to be found so produced. ... I have fre- 

 quently found Gleocapsa polydermica (Kiitzing) formed, as 

 well as other so-called species. After frequent segmentation, 

 the cells are imbedded in an indefinite mass of gelatinous 

 substance/ 



The merely accidental nature, so to speak, of the differ- 

 ence between the Chlorococcus.. product and the Gleocapsa 

 product of the confervoid filament of the Moss is well seen 

 by what occurs in certain filaments where there may be a 

 simultaneous production of the two forms side by side. In 

 reference to this, Dr. Hicks writes : ' The cells of a fila- 

 ment in one or in every part at once begin the process of 

 quaternary segmentation, as before noticed, at first regularly, 

 but shortly after irregularly ; besides this, a certain amount 

 of free-cell formation goes on within the divisions (mother- 

 cells), so that it is difficult to say which kind of cell forma- 

 tion predominates. In this manner large irregular masses 

 of segmentation cells are produced, like some of those re- 

 sulting from the segmentation of the so-called Palmellaceae. 

 The cells set free from them are either Chlorococcus-like 

 cells of variable size, or they are like Gleocapsa, undergoing 

 segmentation in their variable manner. . . . These changes 

 can be readily observed in the colder months. They fre- 



