AND INHERITANCE IN PEDIASTRUM. 401 



them each an angle of 71° -f-- The smallest angle for any of the 

 cells in series II. in all the fourteen colonies is 64° in colony 235, the 

 largest is 78° in colonies loi and 356. The range of fluctuating 

 variation is hence in the fourteen colonies 14° or a little less than 

 20 per cent, of the normal. 



The bases of the cells of series III., as the table shows, subtend 

 angles varying in the averages from 35.6° to 37.1°, 36° being the 

 typical angle. The smallest angle in this series is 32° and the 

 largest 41°, a range of fluctuation of 9°. While the number of 

 colonies whose angles have been measured is not large, it seems to 

 me evident from the data that there is a marked tendency to equal- 

 ity in the spaces occupied by the cells in each series and that the 

 typical configurations about which fluctuation occurs would give 

 each of the cells of series II. 72° and each of the cells of series III. 

 36°. If we arrange the angular measurements of the cells in series 

 II. in a series so as to show the frequency of angles of each par- 

 ticular value, while there are marked irregularities in the series, we 

 have evidence of chance distribution about the value 72° as a mode. 

 31 angles measuring more than 72° and 29 angles measuring less 

 than 72° (see Table III.). Treating the angles of series III. in the 

 same way we find in spite of fluctuating irregularities 59 angles 

 below the mode at 36° and 58 angles above the mode (Table III.). 

 Here again there is evidence of chance distribution about 36°, the 

 value of the typical angle for such a group with least-surface con- 

 figuration. 



TABLE III. 



Frequency of the Angles of the Various Values. 

 Cells 2-6 Inclusive. 



For P. Boryaniim I have elsewhere ('16) given the data as to 

 the organization of the colony based on the study of an individual 

 selected for its regularity. The comparison of the type dimensions 

 obtained in this fashion with those obtained from averaging a series 



