98 H. F. THACHER. 



Examination of Eudendrium and of Pamaria show that the 

 process is the same as that in Campanularia, except in those 

 secondary points to which the structural differences of the hy- 

 droids would give rise. There being no cup, the tentacles remain 

 separate during absorption, so that there can be no question of 

 fusion taking place. The lower row of tentacles of Pennaria 

 persists somewhat longer than do those on the hypostome, but 

 both ultimately disappear, and in neither form is there a with- 

 drawal into the stalk until the polyp has almost entirely degen- 

 erated. 



The results show that in these three hydroids the method of 

 absorption is the same. No trace of liquefaction of protoplasm, 

 or of withdrawal of the polyp as a whole can be found. The 

 absorption takes place by the degenerating cells of the endoderm 

 and ectoderm being turned into the digestive tract of the colony. 



