84 Charles W. Hargitt. 



these organisms to regenerate in the last detail one of the most 

 highly specialized organs known among Coelenterata. This will 

 be shown more fully in connection with the later account of the 

 histology of the regenerated organs. 



Other series of experiments, continued to June 20, while varied 

 In some aspects of detail, were of substantially the same character 

 and with results quite similar to the preceding. 



In several of the experiments care was taken to so modify the 

 form and extent of the excised portions as to secure evidence as 

 to the Influence of contiguous tissues or parts upon the regenerat- 

 ing organs. In Figure i is shown, for example, several aspects of 

 the mode of excising the rhopalia. For the most part the excision 

 was In the form of a triangular cut from the margin Inward toward 

 the radial canal, as shown in the figure. The dotted line a^ will 

 show also in the same connection the occasional extension of the 

 cut to Include twice the usual mass. In Figure i, h, will be seen 

 another form of operation. In this case the portion cut out was 



Fig. 3. 

 Twin rhopalia regenerated in place of the single original one. 



rectangular Instead of triangular, as In the former. The mass 

 excised in the operation also varied as before. At c, In the same 

 diagram, may be seen another form of excision In which the 

 cut was circular instead of angular, as in the former cases. It Is 

 Interesting to note that, so far as I was able to determine, the 

 form of the excision had no perceptible effect upon the form or 

 rate of regeneration. In the case of the rectangular or circular 

 excisions the new organ appeared in Its typical place at the median 

 position of the upper portion of the notch. In the case of the 

 large or small portions excised In the triangular cuts not the 

 slightest difference could be distinguished. With the exceptions 

 of some two or three cases to be considered, there was not the 



