CHAPTER X 



MEGAZOOIDAL INDIVIDUALS. THE MONO- 

 MEGAZOOIDAL INDIVIDUALS 



We may begin this chapter with a summary of the stages 

 of the evolution of living Continuity up to Megazooidal 

 Individuals : — 



1. In the independent unicellular organism of the 

 Discontinuous Multicellular Individual there is, we may 

 say, Protoplasmic Continuity. 



2. In the Filamentous Individual there is a multiplica- 

 tion of this Continuity in the attachment of single cells 

 in linear series. 



There is little doubt that the main road of Evolution 

 has passed through a primitive form of Filamentous Con- 

 tinuity. It is equally probable, however, that it did not 

 pass thence through any primitive Ccenocytic type. For 

 though the Ccenocytic Individual has most likely evolved 

 from some early polyprotoplastic type, its evolution has 

 been along a side-path which has stopped dead at the false 

 tissue of the higher Fungi. 



3. Thus, passing on from Filamentous, or true cell- 

 serial Continuity, we come to true Lateral Continuity, 

 where the equivalents of many cell-series are compressed 

 together in lateral Continuity to form the tissues of inde- 

 pendent multicellular organisms. These organisms are 

 developed typically on a simple plan, and we have reserved 

 for them the name of " zooids." In its simplest form the 

 zooid is a little cylindrical tube, open at the distal end, 

 and composed of two cell-layers ; and when it leads an 

 independent existence it forms part of the Discontinuously 

 Zooidal Individual. It is this which represents our third 

 stage, the independent " cell " of the first stage being here 

 a continuous cell-multiple ; or it might be said that the 



82 



