146 



STUDIES IN GENEKAL PHYSIOLOGY 



over, I had the opportunity of studying new relations be- 

 tween irritability and body form, and in addition one of the 

 fundamental conditions which underlie growth. These lat- 

 ter observations point to a greater similarity between the 

 general life-phenomena of animals and plants than has thus 

 far been known. 





FIG. 26 



The experiments were made upon Cerianthus membrana- 

 ceus. The animal consists of a long, soft, and smooth 

 cylindrical body, carrying a heavy crown of tentacles at its 

 oral end (Fig. 26, a), while at its aboral end (Fig. 26, b) it is 

 smooth and rounded. 



The tentacles at the oral pole are arranged about the oral 

 plate in two concentric circles; the outer circle consists of 

 long, the inner of thin and short tentacles. In the middle of 

 the circle is situated the oral opening, which serves also the 

 functions of an anus. The body of the animal is hollow 



