The Science of Fingerprints: Classification and UsesUnited States. Federal Bureau of Investigation
Science
The Science of Fingerprints: Classification and Uses
United States. Federal Bureau of Investigation
Fingerprints
Figure 316 at first glance appears to be an accidental whorl, but on
closer inspection it proves to be a loop. Although there are three
delta formations present, it should be observed that recurving ridges
appear in front of only one (D-1).
Figure 317 has the general appearance of a loop. The looping ridge A,
at the center, has an appendage B abutting upon its recurve. The
abutment is at right angles and therefore spoils the recurve. The
pattern is a tented arch.
Figure 318 is a tented arch which approaches both the loop and the
whorl type patterns. It cannot be considered a whorl, however, as the
recurve on the left is spoiled by an appendage (figs. 58 and 59). Nor
can it be a loop because there is no ridge count across a looping
ridge. The pattern, then, is a tented arch of the type possessing two
of the basic characteristics of the loop and lacking the third. The
delta and the sufficient recurve are present but the ridge count is
missing.
Figure 319 seems at first glance to be a double loop. It will be
noted, however, that the inner delta formation would be located upon
the only looping ridge of the upper loop formation. Since the delta
would be located on the only recurve, this recurving ridge is
eliminated from consideration. The pattern is classified as a loop.
Figure 320 is a loop of two counts, with the delta at B. There is a
ridge making a complete circuit present, but point A cannot be used as
a delta because it answers the definition of a type line. It should be
considered a delta only if it presented an angular formation. Placing
the delta upon the recurve would spoil that recurve.
[Illustration: 318]
[Illustration: 319]
Figure 321 shows two separate looping ridge formations appearing side
by side and upon the same side of the delta. The core in such case is
placed upon the nearer shoulder of the farther looping ridge from the
delta, the two looping ridges being considered as one loop with two
rods rising as high as the shoulder. The ridge count would be four
(fig. 49).
Figure 322 is an accidental whorl. It is classified thus because it
contains elements of three different patterns, the loop, the double
loop, and the accidental. In such case the order of preference
governs. The delta at the left is point A. The delta at the right is
point C. This point becomes the delta since it is the point nearest
the center of the divergence of the type lines. Point B is eliminated
from consideration as a delta since type lines may not proceed from a
bifurcation unless they flow parallel after the bifurcation and before
diverging.
[Illustration: 320]
[Illustration: 321]
[Illustration: 322]
Figure 323 is a loop. There are two delta formations but the dots
cannot be considered as obstructions crossing the line of flow at
right angles. This precludes the classification of the central pocket
loop type of whorl.
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