l893 . BIOLOGICAL THEORIES. 217 



(3.) That Lucevnavia is a still further modified (" degenerate ") 

 descendant of some free-swimming medusae of one or more species ; 



(4.) That the degeneration and disappearance of the tenta- 

 culocysts, when these ceased to be of use for the function I ascribed 

 to them, supports the view I have expressed in a former essay on the 

 subject of their function. 



REFERENCE. 



1. Clark, H. J. — Lucernarias and their Allies. Smithsonian Contributions 

 to Knowledge, vol. xxiii., 1881. 



C. Herbert Hurst. 



