CHAPTER III 



THE GREEN CELLS OF CONVOLUTA ROSCOFFENSIS 

 AND THE PART THEY PLAY IN THE ECONOMY 

 OF THE PLANT-ANIMAL. 



IT is not only on account of their behaviour, as 

 exhibited by the tropistic movements and periodic 

 phenomena which we have recorded, that the plant- 

 animals C. roscoffensis and C. paradoxa attract the 

 attention of the biologist. The most superficial 

 microscopic examination is sufficient to convince 

 him that their tissues are not like those of other 

 animals. The green cells of C. roscoffensis and 

 the yellow-brown cells of C. paradoxa arrest his 

 attention. In regular and close rows, just beneath 

 the surface of the body, lie the green cells of 

 C. roscoffensis, each so minute as to be invisible to 

 the unaided eye and yet so numerous as to be the 

 source of the dark, spinach-green colour of the 

 animals (Frontispiece and Fig. 14). Though less 

 numerous and less regularly arranged, the yellow- 

 brown cells which lie beneath the skin of C. paradoxa 

 are, like the green cells of the former species, striking 



