MEDUSA OF MICEOHYDRA RYDEKI. 635 



On the Freshwater Medusa liberated by Micro- 

 hydra ryderi, Potts, and a Comparison 

 with Limnocodium. 



By 



Ed\var«l T. Bro^nic, B.A., 



Zoological Research Laboratory, University College, London. 



With Plate 37. 



Through the kindness of Professor Ray Lankester, I 

 have had the pleasure of examining* a specimen of the 

 Medusa liberated from the freshwater Hydroid Microhydra 

 ryderi. 



The veteran American naturalist, Mr. Potts, of Philadelphia, 

 recently sent to Professor Lankester a manuscript on " Known 

 Forms of Medusae Inhabiting Fresh Water,'^ for publication 

 in the ' Quarterly Journal,^ and this communication of mine 

 forms a kind of appendix to it ; it should be regarded as such, 

 since I have before me an advanced proof of Mr. Potts' 

 paper. The title given by Mr. Potts to his communication 

 did not adequately convey the importance of its contents, and 

 has been modified accordingly by the editor. Mr. Potts has 

 at last given us a description with excellent figures of the 

 Hydroid phase of Microhydra and the first figure of the 

 Medusa. 



When Professor Lankester showed me the original draw- 

 ings of Microhydra I noticed the remarkable resemblance 

 between the hydroid phase and that of Limnocodium, but 

 we were doubtful about the Medusa, as Mr. Potts had not 

 given a detailed description of it. Since we were not sure 

 about the presence of sense organs. Professor Lankester asked 



