26S THE BIOLOGY OF HYDRA : 1961 



MUSCATINE: Yes, very often one sees regional differences. How- 

 ever, I am not sure of the significance of this. 



BURNETT: I mention this because I had a chance to observe a 

 very interesting green hydra in Brien's laboratory. This animal ( H. 

 viridis) underwent what seems to be a somatic mutation. The 

 peduncle on this form resembles a stolon and is several times larger 

 than the gastric region. The whole animal may be one and a half 

 inches long, surprising dimensions for a green hydra. The peduncle, 

 unlike that of normal H. viridis, contains more algal bodies per cell 

 than the gastric region. Also food materials pass into this region in 

 greater amounts than into a normal peduncle. What is most inter- 

 esting is that this mutant form not only reproduces asexually by 

 budding but also by pinching off the distal portion of its peduncle. 

 This detached portion then regenerates into a complete organism. 

 It is marvelous! 



EAKIN: Did you try increasing the oxygen tension while growing 

 the albino hydras? 



MUSCATINE: Well, we're just getting into gas analysis. We have 

 conducted preliminary experiments growing green and albino hydra 

 in air plus 0.4% COo, but the results were not definitive. Eventually 

 we will control pCOo and pOo. 



EAKIN: It will be interesting to see if the high oxygen tension 

 can reverse some of the effects observed in the absence of the algal 

 chlorophyll. 



MUSCATINE: Yes, that's a good way to attack this, going through 

 the algae. I would also like to see if green hydra show an action 

 spectrum for growth rates which can be related to the absorption 

 spectrum of chlorophyll. 



