NERVOUS S-YSTEM OF TUNICATE 59 



ence of ganglionic influence. Final judgment, however, must 

 be suspended until the remainder of the evidence has been 

 considered. 



In table 5 has been brought together the rates in seconds per 

 every 10 beats. The first or upper portion of the table gives 

 the rates for ventrad series and the last or lower portion the rates 

 for dorsad series. For animal 15 the normal rate was 55", 55", 

 (29") for one reading, and 58", 55", 53" for a second ventrad 

 series. The number in parenthesis is for the last incomplete 

 set of beats, here five instead of ten. There is a fluctuation of 

 3 beats between the initial sets 55 and 58 for the two readings. Of 

 the six readings for the normal beat of no. 16 .the figures range 

 from a minimum of 54 to a maximum of 69. Since the third 

 reading was exceptionally high, the average initial rate would be 

 57" for the first ten beats. Animal no. 18 shows 53" for the 

 single normal reading obtained. 



When the nerves between ganglion and heart were severed, 

 the initial figure dropped to 42 for no. 15, to 51 for no. 18, indi- 

 cating by the fewer seconds required in each case for the initial 

 10 beats a more rapid rate of beat. No. 15 thus shows the 

 greater acceleration of the two as a result of the operation. 



The following day, however, after recovery had occurred, the 

 rates had returned to 53" and 57" for no. 15 and to 57" and 54" 

 for no, 18. In the first case 57" lies between the 55" and 58" 

 of the normal reading above, and 54" in the second case is but 

 one second greater than the normal. 



When the ganglion was extirpated the initial figure again 

 dropped to 43" for no. 15, 42" for no. 16, and to 50' for no. 18, 

 indicating renewed acceleration. Recovery was recorded for 

 the first two animals only: for no. 15" it returned to 51 and for 

 no. 16 to 70". In the case of no. 15 the return was not quite 

 to the normal, while for no. 16 it was to a figure higher than 

 the average normal; i.e., in the first case the recovered rate 

 was still slightly accelerated, while in the second it was slower 

 than normal. If the last reading for the recovered rate of no. 

 16 be compared, however, to the third normal reading, they are 

 nearly alike: 69, 67, (7) vs. 69, 64, (7). Since the dorsad series 



