PREVIOUS INTERPRETATIONS OF CNIDARIA 



201 



Fig. 36. Hypothetical evolution of cnidae from secretory cell 

 without solid secretion, (A) to fully developed cnidae (B-F). 



armed proboscis, where poisonous glands are used, together 

 with stilettos, as an effective weapon. 



In the Cnidaria genuine cnidae only appear, as has already- 

 been mentioned, quite generally and without a single excep- 

 tion. This should not be considered as surprising, since all 

 levels of evolution in the direction towards a genuine cnida 

 can already be observed in Turbellaria. This fact which must 

 be expected if we accept our standpoint, i.e. a progressive 



