iSd HENRY FAKNIIAM PERKINS. 



figure, shortened and shrivelled (Fig. 7). This form arises with- 

 out the slightest traceable connection with the polyp-form, and 

 its appearance seems entirely fortuitous. It is hard to see why 

 it should be so common. 



The plas medium -like larvae remained alive for nearly two 

 months, showing the various forms and movements described. 

 The repeated fission of the individuals resulted in such diminution 

 of the size of the pieces which came from the original individuals 

 that after a time it was impossible to distinguish the bits of living 

 matter from the other particles lying about on the bottom. But 

 during the entire time in which it was possible to recognize the 

 pieces of degenerating larvae, by the evident ccelenterate char- 

 acteristics, the sum total of this substance did not seem to be at 

 all diminishing. It is impossible to assign any satisfactory 

 explanation to the phenomena, but it is not unlikely that the 

 condition of the water in this particular aquarium-jar was 

 peculiar, owing, perhaps, to evaporation which increased the 

 density, or to the introduction, inadvertently, of some chemical. 



While it is not possible to explain the phenomena here de- 

 scribed, or to determine their significance, the facts are stated in 

 the hope that they may call forth other facts which may have a 

 bearing on the same subject. It would be most interesting to 

 discover whether such degenerative conditions occur in any other 

 ccelenterates ; whether they are brought about by any specific 

 external circumstances ; and whether creatures which have 



assumed this condition are capable of resuming their normal form. 

 JOHNS HOPKINS UNIVERSITY, 

 June, 1902. 



