28 HARGITT. [VOL. I. 



not the purpose here to inquire in detail. Further investiga- 

 tions, some of which are under way, will be necessary to afford 

 sufficient data for any adequate judgment. 



The particular class of experiments to which I purpose to 

 direct attention at this time pertains to another group of 

 organisms, and one upon which, so far as I am aware, nothing 

 directly has been done, though incidentally it has been referred 

 to in connection with another subject, and will be duly noted 

 in another part of the paper. The organisms referred to are 

 the medusae. In connection with the previous work already 

 noted, the thought of extending these experiments to the 

 medusae occurred more than once, but owing to their peculiar 

 delicacy and highly specialized character, was dismissed as of 

 doubtful practicability. The presence, however, of consider- 

 able numbers of Gonionemus vertens, a preliminary report upon 

 which was made during the previous year by Dr. Murbach, and 

 the capacity of which to endure confinement in small aquaria 

 was rather marked, revived the previous conception, and after 

 reflection it was determined upon with some hesitation. 



Accordingly a small number of these medusae were obtained 

 and placed in small table aquaria, and upon them a series of 

 extremely simple experiments made, such as the excision of a 

 few tentacles, notching the margins, etc., more from a spirit 

 of curiosity than of expectation. When, therefore, upon the 

 following day I noted that the mutilations were healed in sev- 

 eral cases and that there was an evident tendency toward a 

 restoration of excised parts, interest was only exceeded by 

 surprise. However, I found, upon a brief review of the work 

 of Romanes 1 on the Nervous System of Jellyfish, etc., that 

 he had called attention to the fact of the capacity of these 

 organisms to regenerate mutilated tissues, but no work was 

 done in connection with the observation. Later Eimer also 

 made certain experiments upon jellyfishes of a similar sort, 

 but without recording any tendency toward active physical 

 regeneration, though demonstrating the recovery of nervous 

 activity. 2 I may incidentally note the fact that in none of my 



1 Jellyfish, Starfish, and Sea Urchins, p. 103. 

 - Organic Evolution, pp. 345 et seq. 



