Regeneration in Rhizostoma Puhno. 87 



and that the rhopalia are essentially independent dev-elopments 

 such as are found during the process of regeneration? I merely 

 raise the suggestion as it has been forced upon my attention in 

 course of these experiments. It seems worth farther investigation. 

 In this connection may be briefly described a phenomenon which 

 only came under critical observation late in the course of the 

 experiments, and which for lack of material it was impossible to 

 follow out to conclusive results. Among the last of the series 

 two large specimens were operated upon as follows : In the 

 first all but one of the rhopalia were excised, while in the second 

 all but two were removed. In both cases there was distinctly 

 noticeable an aberrant, rotary sort of swimming movement, the 

 animal revolving in an irregular circle, instead of directly for- 

 ward or upward as is usual. Examination showed that this in- 

 clination of the body in swimming was constantly in the direction 

 of the remaining rhopalia, which would seem to suggest that 

 perhaps they functioned something after the nature of equilibrium 

 organs. I do not recall that this feature has been referred to by 

 the investigators previously cited, and very much regret that it 

 was not practicable for me to carry out such additional experi- 

 ments as would have afforded more definite conclusions. It must 

 suffice to merely mention the matter, hoping that at some time 

 someone may be able to secure definite conclusions by extended 

 experiments not only upon this medusa but perhaps on others 

 as well. 



III. ABNORMALITIES. 



In connection with observations upon several specimens which 

 had become degenerate or perhaps pathologic, resulting from un- 

 favorable conditions of some of the aquaria, or perhaps in some 

 cases due to the depleting effects of the experiments, as in the 

 case of the first experiment cited in this paper, occasion was taken 

 to examine somewhat in detail the observations and experiments 

 of Uexkiill and to compare cases coming under my own observa- 

 tions during the course of the experiments. 



In one specimen which had shown evident decline of vigor and 

 upon which there appeared certain exumbrellar blotches or cor- 



