Regeneration in Cassiopea 273 



stolons alone. After a second removal it develops one or more 

 slender stems as well as the stolons, after a third removal two or 

 three strong stems and only one or a few slender stolons, and 

 finally after a fourth removal no stolons at all, the whole growth 

 consisting of one or two very stout stems. 



To further test the question of the influence of successive 

 injury upon regeneration, I made a study of the problem in the 

 chelae of the Gulf-weed crab, Portunus Sayi, in the Scyphomedusan 

 Cassiopea xamachana and in several other forms. The report 

 on the first of these is now in press, and the data show that while 

 the second regeneration is greater than the first, nevertheless, when 

 the age factor is eliminated the two are exactly alike. In Cassiopea, 

 however, in which the age factor is also eliminated, the margin 

 shows in every case a greater rate of regeneration after the second 

 than after the first removal. The material on several other forms 

 is now being worked up. 



J The Relation of Functional Activity to the Rate of Regeneration 



In view of recent discussions concerning the relation of form 

 regulation to functional activity a comparison of pulsating with 

 non-pulsating disks of Cassiopea is of special interest. Con- 

 trary to the general view that functional activity is an aid in 

 eff^ecting form regulation, it was found that pulsating individuals, 

 with two exceptions, showed a slower rate of regeneration than 

 non-pulsating ones. The result indicates that there is need of 

 further investigation along this line before general conclusions 

 are made. 



