PHYSIOLOGICAL VARIATIONS IN PARAMECIUM 



481 



Diagram 2 



The mean length and breadth and the standard deviation are 

 given for each measurement and for each of the 16 hnes in tables 

 1 and 2 arranged in quadrants. The means for length alone are 

 given in table 3 arranged in serial order for both periods. From 

 the latter table (column 3) it is evident that three distinct groups 

 separated from one another by at least 10 microns were present 

 in the first series of measurements. The means of the second 

 series of measurements were greater in all cases than those of the 

 first, the actual differences in microns for lengths only are graphs 

 ically shown in diagram 2. 



The tables show that certain lines are highly variable both as 

 to length and breadth. Some, notably 31, increased in all di- 

 mensions; others, notably 16, 15, 13 and 21, increased in length 

 at the expense of breadth. Some lines, notably 21, 26, 13, 20, 7 

 and 1 are more stable. Diagram 2 shows that quadrant A, con- 

 sisting of J 1, 7, 8, and 21, is less variable as a group than any of 

 the other quadrants. As the sequel will show the quadrant A 

 lines are all conjugating lines while the others are not. This 



