210 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



The year 1936 for TTP 24 (table 146) has one with unity and 

 one with multiplicity; 1937, one with unity and three with multi- 

 plicity; 1938, all five with unity; 1939, four with unity and one 

 with multiplicity; and 1940, one with unity and four with multiplic- 

 ity. Branch-years number 21, of which 12 have unity and 9 have mul- 

 tiplicity. Among these branches, agreement is 14 percent. 



The year 1944 for WAp i (table 147) has one with unity and one 

 with multiplicity. This gives 100 percent disagreement. 



The year 1944 of VVPe i (table 148) has two branches with unity, 

 four with multiplicity. Agreement is 33 percent. 



The year 1932 of XSC i (table 149) has two branches with mul- 

 tiplicity; 1933, three branches multiple ; 1934, three multiple ; 1935, 

 three multiple; 1936, four multiple; 1937, four multiple; 1938, four 

 multiple; and 1939, four multiple. There is 100 percent agreement. 



The year 1936 of XSC 2 (table 150) has all three branches mul- 

 tiple; 1937, all three multiple; 1938, one with unity and two with 

 multiplicity; and 1939, all three multiple. There are 12 branch-years, 

 of which I has unity and ii multiplicity, giving an agreement of 83 

 percent. 



The year 1937 for XSC 8 (table 151) has all six branches with 

 unity; 1938, all six multiple; 1939, one with unity, five with mul- 

 tiplicity; and 1940, all six multiple. Of the 24 branch-years, 7 have 

 unity and 17 have multiplicity. This gives an agreement of 42 percent. 



The year 1937 of XSC 12 (table 152) has two branches with unity 

 and one with multiplicity; 1938, all three multiple; 1939, one with 

 unity and two with multiplicity ; and 1940, all three multiple. Of the 

 12 branch-years, 3 show unity and 9 multiplicity. This comes out as 

 an agreement of 50 percent. XSC 12 (table 152) illustrates well what 

 has been pointed out heretofore concerning longitudinal variation : an 

 increase inward in numbers or area of sharply bordered growth layers 

 within a single year (12-1, 1938; 12-2, 1938), an increase outward 

 (12-1, 1939; 12-3, 1937), no change within the compass of the sec- 

 tions (12-2, 1939, 1940), or a change in both directions (12-1, 1940). 



The year 1937 of XSC 13 (table 153) has two branches with unity 

 and one with multiplicity; 1938, all three multiple; 1939, all three 

 multiple ; 1940, one with unity and two with multiplicity ; and 1941 

 has two branches with multiplicity. Of the 14 branch-years, 3 have 

 unity and 1 1 have multiplicity. This gives an agreement of 57 percent. 

 The year 1941 of XSC 13 (table 153) differs from previous years in 

 that all three branches were frozen artificially June 14, 1941, at about 

 the same temperature and for approximately the same length of time. 

 Branch XSC 13-1 was permitted six days of recovery before being cut 



