Key points are not available for this paper at this time.
Page 99, fifth line of footnote, for Sewell Wright, read Sewall Wright. Page 99, last line of footnote, for B n F n G n -1 read B n -F n -1-G n -1. Page 117, interchange lines 18 and 19, placing in sections (12), (13) and (14) above the preceding line. Page 144, fourth line from
H. S. Jennings (Thu,) studied this question.