Regeneration in Rhizostoma Pulmo. 93 



shown In the figure, It has not been possible to trace these fibers 

 into any cellular plexus, or ganglion, such as has been claimed to 

 exist here. Since however my observations In the present instance 

 have been almost entirely restricted to phases of regeneration, it 

 will not be pertinent to discuss the question farther. 



As will be seen there Is still a continuous connection between 

 the cavity of the distal portion of the organ and the radial canal. 

 This connection Hesse, '95, has shown in figures of normal or- 

 gans in maturity, but In the present examinations I have found it 

 when fully regenerated to become entirely solid throughout the 

 llthocyst region, the radial canal ending abruptly at its basal end, 

 which is shown almost closed In the figure under consideration. 



In the rhopalial cavity, rh. c, which at this time Is nearly spher- 

 ical, there is present a radiating network of delicate fibers, poorly 

 shown in the figure, which seem to diverge from a point on the 

 lower surface and extend entirely across the cavity apparently 

 attaching to the opposite wall. I should consider these fibers of 

 the same nature as those shown In Figure 5 near the terminus of 

 the line rh. c. Though It has not been possible to critically trace 

 the details of the process it seems entirely probable that the ento- 

 dermic epithelium of this region becomes gradually differentiated 

 Into fibers which form the Intricate network within which the 

 llthocysts are later deposited. Within this network may be found 

 during the various stages of development the gradual metamor- 

 phosis of this entodermic cell mass, the nuclei of the cells often 

 remaining as permanent elements of the organ. Some of the 

 more prominent of these are shown In the figure, and phases of 

 the metamorphosis may be detected near the narrow slit-like 

 canal, just beyond the terminus of the radial canal. 



Within the network may also be traced the deposition of the 

 pigment characteristic of the organ. 



Concerning the histology of the regenerated oral and gastric 

 organs it has not seemed essential to make special Inquiry, since 

 in what has already been shown In connection with the more 

 highly differentiated tissues of the marginal organs It would seem 

 that no serious doubt can remain as to normal histogenic pro- 



