REACTIONS OF ANIMALS. 



TABLE VIII. 



105 



-Showing the rating of the different species studied when the turnings back from 

 the modified air and percent of time in the two halves of the experimental cages 

 are regarded as of equal value. The ratings are obtained from the percent of total 

 turnings from the halves and the percent of time in the halves. The differences 

 between the two percents in each case were added and divided by 2. When the 

 greatest number of turnings is from the end in which least time was spent the 

 turnings and time are of the same sign (+ or ). 



2. Comparisons. 



(a) Integument. An inspection of Table VII. shows that the 

 animals killed by rapid evaporation fall into two distinct groups : 

 (a) those dying with an evaporation varying from 0.07 to 5.40 

 c.c. after an exposure varying from five to one hundred and 

 sixty-five minutes, and (6) those dying with an evaporation of 

 31.0 to 42.0 c.c. after an exposure of from 1,300 to 2,200 minutes. 

 The first group is made up of soft-skinned amphibians, the second 

 of chitin-covered arthropods. Even though the arthropods were 

 much smaller (Hill, '06, p. 267) they lived from eight to four hun- 

 dred and fifty times as long as the amphibians. The loss of 

 water through a tracheal system should be at least as great as 

 through lungs; the difference is probably primarily due to the 

 character of the integument. 



(&) Reaction, Survival-Time, and Habitat Preference. A com- 

 parison of Tables VII. and VIII. shows that in general there is a 

 rough relation between survival time and reaction among animals 



