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. 



1 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. 

 'See curve EF, fig. 12. 



hAAA/WWWWlAAAAAAAA/VWVWWWV^ 



sea water 



31.25C. 



\mmm 



(60 sea water -^- x^ KCV .Ci+m Si^iS 



\N\N\I\N\J\I\{\IW\JW^^ 



-^ At o XL T 



a.+ t er w a-vcls 



-t 



Zo.l 



VW\AAAAA/\AA/VV\AA/'v/W~\A/\/V\/W\AA/V\AAAA/V'\yVVVW\AAA 



a.5teT one "houv 31* 



100 c,ea water -f 5 KCl 3\!\ 



VV\AAAAAA/VV\AAAAAAA/\AAAAAAAAAAAA/\AAAA/V\AAAAA/^^ 



.. .. 3h- -m vT\T^ tres oL^ tevwcT-T els 31°) 



100 sea wsi-ter r^ 7^ KCl ■^y'.i. 



1 houY A-^terwards 

 Fig. 13. 



31% 



