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J. S. HUXLEY AND G. R. DE BEER 



the cells appear as in PL 26, fig. 8, still with a definite cell 

 boundary. Nematocysts only appear in the gastrovascular 

 cavity in late stages of resorption, after rupture of the 

 mesoglaea at the base of the tentacles. The bulging in of 

 the basal mesoglaea before breaking is well shown in PI. 26, 

 fig. 3, left-hand tentacle. 

 Appearances sometimes occur in Obelia which seem to show 



Text-fig. 5. 



Campanularia. End of stage 4. The zooid is represented only by 

 a small stalked knob containing a mass of pigment, mostly 

 brown with some orange granules. (Camera lucida.) 



that phagocytosis is taking place. This wais corroborated on 

 a specimen of Campanularia (the one shown in Text-fig. 6) 

 which was accidentally ruptured : numerous cnidoblasts with 

 contained nematocysts were then seen ; but in addition, 

 nematocysts were found inside cells much larger than cnido- 

 blasts ; frequently two would be seen within a single large 

 cell (see Text -fig. 7). 



