[Figs. 185-190]
The reason that figure 185 is given the classification of a tented arch is because of the presence of all the loop requirements with the exception of one, which is the recurve. In this pattern appear three ending ridges. The lowest ending ridge provides the delta, and the other two by the convention explained previously, provide the ridge count. It is a tented arch, then, of the type approaching the loop, with two of the characteristics, but lacking the third, a recurve. Figures 186 and 187 are tented arches of the same type. A close examination of these prints will reveal that when the imaginary line is drawn between delta and core no ridge count across a looping ridge can be obtained. It must be remembered that the core of a loop may not be placed below the shoulder line. Lacking one of the three characteristics of a loop, these patterns must be classified as tented arches. When figure 188 is examined, it will be noticed that the recurve is spoiled by the appendage abutting upon it between the shoulders at a right angle, so it must also be classified with the tented arches. In figure 189, the only possible delta must be placed upon the looping ridge, thus preventing a ridge count although delta and recurve are present. Figure 190 is assigned the classification of a tented arch. One of the requirements of a loop type is that the ridge enters on one side, recurves, and makes its exit on the side from which it entered. This, of course, makes it necessary that the ridge pass between the delta and the core. It will be noted from this figure that although this ridge passes between the delta and the core, it does not show any tendency to make its exit on the side from which it entered, and therefore the loop classification is precluded, and it is a tented arch.
The whorl
The patterns to which numerical values are assigned in deriving the "primary" in the extension of the Henry System of fingerprint classification used by the Federal Bureau of Investigation are the whorl-type patterns, which occur in about 30 percent of all fingerprints.
The whorl is that type of pattern in which at least two deltas are present with a recurve in front in each. Figures 191 to 193 reflect the minimum requirements for the whorl.
[Figs. 191-193]
It is important to note that the above definition is very general; however, this pattern may be subdivided for extension purposes in large groups where whorls are predominant. Even though this extension may be used, all types of whorls are grouped together under the general classification of "Whorl" and are designated by the letter "W".
The aforementioned subdivisions are as follows: The Plain Whorl, The Central Pocket Loop, The Double Loop, and The Accidental.