iv] GREEN CELLS OF CONVOLUTA 113 



only the outermost contain a distinct nucleus, others 

 possess deep-staining granules, and others no nuclear 

 material whatever. A parallel suggests itself between 

 the green cells of C. roscoffensis and the red blood- 

 corpuscles of the higher vertebrates. As the red 

 discs are enucleate, partial cells budded off from the 

 nucleated red cells, so may the green cells be regarded 

 as enucleate, partial cells budded off from the outer- 

 most, nucleated green cells ; and, as the red blood cor- 

 puscles are of limited life and specialised (respiratory) 

 function, so are the green cells of C. roscoffensis of 

 limited life and of specialised (photosynthetic) 

 function. 



The green cell, devoid of nucleus, would not, 

 however, appear to be shut off from all nuclear 

 influences. For the enucleate green cell may be 

 connected by fine processes with another green cell 

 still possessed of nuclear substance (Fig. 17, p. 85). 

 Moreover, such green cells as are without nuclear 

 material are accompanied by a large attendant nucleus 

 of animal origin. This close association of " attendant 

 nucleus" and green cell is shown in Fig. 17, Mes.C. 

 It may be that the attendant nuclei are those of 

 "wandering cells'" of the animal which lie in wait 

 for enucleate green cells and, at a subsequent stage, 

 digest them. 



The astonishing closeness of the relationship 

 between animal and green cells offers some support 



K. 8 



