CO-ORDINATION. 145 



ever, periplieral irritability returned, as shown by 

 responses to nipping of the neuro-muscular sheet. 

 The animals were now in the same condition as 

 when amTesthesiatod by cafiein or other central 

 nerve-poison ; but in a few minutes later central 

 or reflex irritability also returned, as shown by 

 single responses to single nippings of the tentacles. 

 Last of all spontaneity began to return, and was 

 in some few cases conspicuously marked by a want 

 of co-ordination, all parts of the margin originating 

 impulses at different times, with the result of pro- 

 ducing a continuous flurried or shivering movement 

 of the necto calyx. After a time, however, these 

 movements became co-ordinated ; but in most cases 

 w^hen a swimming bout had ended and a pause 

 intervened, the next swimming bout was also in- 

 augurated by a period of shivering before co-ordina- 

 tion became established. This effect mio^ht last for 

 a long time, but eventually it, too, disappeared, 

 the swimming bouts then beginning with co-or- 

 dinated action in the usual way. 



