Regeneration in Rhizostoma Pulmo. 91 



seems also to be present the middle lamella, though less sharply 

 defined than at a somewhat later period. There appears to be a 

 rapid proliferation of the cells of the entoderm near the terminal 

 portion where they form a mass as shown in the figure, though, as 

 mentioned above, it was not possible to distinguish evidence of 

 mitosis. 



It is interesting to note at even this early stage the incipient 

 phases in the regeneration of the sensory areas (Fig. 2, s. e.) just 

 above and below the rhopalium. The regeneration of the hood 

 is also shown at h. 



\ — eel. 



mgl. 



s.e. ent. 



Fig. 5. 



Section of regenerating rhopalium. rh. c, rhopalial canal ; other letters 

 as in Fig. 2. 



In Figure 5 is shown a section taken in the same plane as the 

 former, but at a somewhat later stage of development. The 

 rhopalium has apparently attained nearly full size, but lacking as 

 yet any development of otoliths, though in the network shown at 

 rh. c. there is apparently evidence of a differentiation preparatory 

 thereto. There is also shown here the thinning out of the ecto- 

 derm of the distal portion of the organ as seen at ect. 



The sensory areas and epithelium above and below are here 

 seen to have acquired almost their typical form and character as 



