A Freshwater Medusa 213 



living in fresh water. Hundreds, even thousands of the 

 animals, a considerable number of which had arrived at 

 the adult stage, may be seen swimming in the tank, the 

 temperature of the water being from 80 to 90 F. They 

 are from one-eighth to half an inch in diameter, the great 

 majority appearing to be males. These Medusa are allied 

 to the Trachomedusae and Narcomedusae of Haeckel, but are 

 a new generic form, for which he had proposed the name 

 Lymnocodium. He and Professor Lankester had agreed 

 on the specific name Sowerbii. Whether it is developed 

 directly from the egg or from an intermediate hydroid 

 trophosome, is not yet determined, but the former appears 

 to be the more probable, as no hydroid polyp has been 

 observed in the tank. It may be supposed that the ova 

 were introduced with the roots of some foreign plants, 

 perhaps from the West Indies. 



Nov. 25th, 30ist meeting. Mr. Galton spoke of the 

 progress made in applying the system of composite photo- 

 graphs to delineate the more characteristic features of 

 disease. This was being done at Guy's Hospital. Sir 

 J. Paget said that hitherto the physiognomy of diseases had 

 not been accurately portrayed. 



Dec. i6th, 3O2nd meeting. Professor Roscoe referred 

 to a paper by Mr. Carnelley of Sheffield (to be read that 

 evening at the Chemical Society l ), which maintained that 

 in vacua ice, corrosive sublimate, and camphor may be 

 raised to temperatures high above their melting points 

 without being liquefied. 



1881. Jan. 2Oth, 3O3rd meeting. The subject of Mr. 

 Carnelley 's paper was resumed, and doubts were expressed 

 by one member in very positive terms whether his experi- 

 ments and conclusions were valid. 2 



Mr. John Aitkens's communication to the Royal Society 



1 The Minute on Dec. i6th says, " read to the Chemical Society," but 

 on Jan. 2oth, " to the Royal Society." It was read to the latter Society 

 (Proc. R.S. vol. xxxi. page 284). 



* According to the Minutes this member oSered to bet another more 

 favourably disposed 100 to 1, but the exact terms of the bet could not 

 be settled, though some members so far unbent as to make the endeavour. 



