448 THE BIOLOGY OF HYDRA : 1961 



DISCUSSION 



BURNETT: I might mention that if the end of a bud is excised 

 early in its development, the remaining part will regenerate while 

 still attached to the tissues of the parent. This suggests that cellular 

 divisions are occurring within the tissues of the bud proper. More- 

 over, we have been able to demonstrate that after the bud hypo- 

 stome reaches a certain distance from the parent column, it develops 

 a growth region of its own. The tentacles of the bud arise only when 

 the tip of the bud has grown some distance from the parent. Tenta- 

 cle formation is dependent upon cellular divisions in the budding 

 tissue itself, and tentacular material is not furnished by the parent. 



CLAYBROOK: I'd like to report an observation about which we 

 have no further information. Occasionally, in cultures of Hydra lit- 

 toralis growing at a minimal rate while being fed the heated Artemia 

 diet which I reported on yesterday, we find buds that fail to form 

 hypostomal tentacles or mouth. They may remain attached to the 

 parent for days or weeks. Sometimes they detach after they have 

 differentiated a basal disk, but some still do not produce anv ten- 

 tacles. Under these conditions, they cannot eat and eventually 

 disintegrate. 



