52 



Papers from the Marine Biological Laboratory at Tortugas. 



being very great in comparison with the size of the animals and the solutions 

 being changed frequently. 



It appears that a very slight increase over and above the normal con- 

 centration of the potassium ion is a permanent stimulus. 



Table 15 shows the relative rates of 3 normal medusae and i subumbrella 

 ring of Cassiopea xamachana in sea-water to which increments of a 0.64 

 molecular solution of KCl have been added. 



Table 15. 



> These medusae recovered their normal rates after being returned to sea-water. 



' Stopped in less than one hour. This medusa recovered its normal pulsation when returned to sea-water. 



' See curve CD, fig. 12. 



* See curve AB, fig. 12, and record, fig. 13. 



5 See curve EF, fig. 12. 



fiAA/WWWV\/\A/VW\AAAA/W\/W\/WV^^ 



sea. water 'h^isC. 



VJWWWJ 



lOO sea. water + z^ KCV .t4--m. 2> " 2 5 



W\/W\AA/Wi/WV\A/W\MA/W\/WWWW\/WW\/\AA/\^ 



\ ^^o-- 



a.4-tev wa-vcls 



Z0.1 



VW\AAAAAAAAAAA/W''y\A/^A/\AAAA/\AA/V\AAAAA/'^/VAAA\VVV\AAA/^ 



3-5 ter one "hour 31* 



100 c,ea watev -^ 5 KCl 



VVV 



3i!i 



VVV\AAAAA/VV\A^\AA/V\A/\AAAAAAAAAAAAAAAAA/\AAAAAAAJ^^ 



.... 3h- -mwTi\i.tes aftevwATcls 3,i\ 







loo sea water -^ 7^ KCl ?).'2- 



1 \iouY A-^terwardS 

 Fig. 13. 



3i*.C 



