If the ridge enters the pattern area from a point below the divergence of the type lines, however, the delta must be located at the end nearer the core. Ridge A in figure 30 is of this type.
[Fig. 30]
In figure 31, A—A and B—B are the type lines, with the dot as the delta. The bifurcations cannot be considered as they do not open toward the core.
[Fig. 31]
In figure 32, the dot cannot be the delta because line D cannot be considered as a type line. It does not run parallel to type line A—A at any point. The same reason prevents line E from being a type line. The end of ridge E is the only possible delta as it is a point on the ridge nearest to the center of divergence of the type lines. The other type line is, of course, B—B.
[Fig. 32]
The delta is the point from which to start in ridge counting. In the loop type pattern the ridges intervening between the delta and the core are counted. The core is the second of the two focal points.