172 



K, S. LASH LEY 



TABLE 9 



Effects of starvatio7\ oj parents upon the number of tentacles of their buds; second 



experiment 



repeated with polyps from two clones and results were obtained 

 which made it certain that starvation of the parent leads to a 

 reduction of the number of tentacles of its progeny. The results 

 of this experiment are shown in table 9. 



The parents recorded in this experiment were old polyps 

 taken from mass cultures. Their mean number of tentacles 

 already exceeded the means of the clones from which they came, 

 so that any considerable increase in their numbers of tentacles 

 during the brief time of the experiment was not to be expected. 

 Hanel's data, however, prove that starvation tends to inhibit 

 the addition of tentacles in parents and this experiment shows 

 that the buds of starved parents have fewer tentacles than those 

 of normal ones. This condition, occurring among a large num- 

 ber of polyps subjected to unequal and fluctuating environmental 

 conditions would undoubtedly lead to a slight degree of resem- 

 blance between parent and progeny, even if there is no true 

 inheritance of parental variations. 



Effect of injury. Twenty mature Hydras were cut in two trans- 

 versely and kept until both halves had regenerated. Each 

 half was kept in a separate dish and the buds which it produced 

 after regeneration was complete were recorded. Altogether, 

 287 buds were obtained from the 40 freshly regenerated polyps. 

 The mean number of tentacles of the clone from which the orig- 

 inal 20 were derived was, at this time, 6.91 ±0.03. The mean 



