STINGING-CELLS IN CRASPEDOTE MEDUSA. 763 



On the Origin and Migration of the Stinging- 

 Cells in Craspedote Medusse. 



By 

 Cliaiic'!!» L. Boiilcii^^or, M.A.(€aiMb.)i 



Lecturer on Zoology in the University of Birmingliam. 



With Plates 42 and 43 and 5 Text-figuves. 



Contents. 



1. Introduction ..... 



2. The Stinging-cells of the Adult Medusa of Mcerisia 



3. Migrating Stinging-cells in other Medusse . 



4. The Development of the Medusa of Mcerisia 



5. General Conclusions .... 



6. Bibliography ..... 



PAGE 



763 



765 



770 

 771 



780 

 781 



1. Inteoduction. 



Lewis Murbacli (1), in 1894^ definitely established the fact 

 that the stinging-cells of the Hydromeduste have the power 

 of active movement in the tissues by the formation of pseudo- 

 podial processes from the cnidoblasts. 



These observations were confirmed by K. C. Schneider^ (2) 

 who published a detailed account of the development of 

 nematocysts in Agalmopsis and other Siphonophora_, and in 

 his paper stated emphatically that : 



" Alle Nesselzellen der Siphonophoren enstehen an locali- 



• Schneider, as early as 1890, pointed out the fact that developing 

 nematocysts were excessively rare in the tentacles of Hydra, and 

 suggested that they might be formed on the body of the animal. He did 

 not, however, pursue the subject any further {vide "Bibliography," 3.) 

 VOL. 55, PART 4. NEW SERIES. 51 



