No. 485] THE FUNCTIONS OF THE SPIRACLE 



293 



morning the fish was at rest, the respiration being verv slow and 

 the spouting infrequent, as described above for the resting condi- 

 tion. I have no record of the precise rates in this case. Tlie 

 fish was then exercised and immediately removed to a shallow 

 tray of water for easier observation. The rate of respiration was 

 markedly increased, rising to 47 inspirations per minute, and a 

 spouting occurred on the average after every nineteenth insj)ira- 

 tion, that is, a little oftener than twice a minute. TK\> avnagc 

 was obtained by counting the number of inspirations within a 

 period covered by eleven successive spouts. The actual number 

 of inspirations between two successive spouts varied from 15 

 to 23. 



In a similar case the rate of respiration while at rest was 22 

 inspirations per minute, with spouting at intervals of several 

 minutes. After exercise the rate of respiration was 39.5 per 

 minute, with a spouting after ever}' seventeenth inspiration, or at 

 the rate of 2.3 spouts per minute. 



(2) A skate which had been undisturbed, so far as 1 know, for 

 two days was found resting quietly against the side of the a(|nannin. 

 The rate of respiration and the frequency of spouting were deter- 

 mined. Then the fish was exercised vigorously for five miiuites, 

 after which it was given five minutes to become quiet so that 

 observations could be made. Following are the results of the 

 experiment. 



Inspirations Inspirations Spoutings 



After exercise 47.5 67 0.71 



Increase 58% .500% 



(3) A skate which had been under experiment was allowed 

 to rest for about an hour. At the end of that time the rates of 

 respiration and spouting were determined. Then durin^r tl)(> next 

 half hour the fish was subjected to some annoyance l>y irritation 



