146 STUDIES IN GENERAL 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 
Mil 
HM =, 
_ SSS 
[| 
ie 
| z 
= 
if 
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, 0) 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 
Digitized by Microsoft® 
