W. F. LOOMIS 



355 



2. Inhibition of Tubiilaria regeneration: Even an amputated 



hydranth can inhibit regeneration in adjacent Tubularia 

 stems (5, 7, 28 ) . This may result from the low intracellu- 

 lar pH that results from high background pCOo produced 

 by bacterial decomposition (and possibly intrinsic respi- 

 ration) of the amputated hydranth. 



3. The Fulton effect in Cordylophora: 



Fulton observed that Cordylophora "may be grown at- 

 tached to microscope slides slanted in 100 ml. beakers. 

 Such cultures may be grown to considerable density, 



TABLE 3 



Rachevsky zone 

 ( see Fig. 2 ) 



Analogous zone 



Factors affecting sexual differ- 

 entiation in hydra 



