1029 
can distinguish three principal types, viz. a division into 7, 5 or 
9 bundles. 
With a division of 7 curves into 7 bundles, the diagram 
BED Be Be Be ee 
1 | 1 
arises, consequently a diagram with 7 onecurvical bundles. It is 
represented in fig. 1 by a. 
(A) 
