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WCDX EXTENSION: In the extension used in the Federal Bureau of
Investigation for the large whorl groups, the type of whorl is
designated by the symbols W, C, D, or X for the index fingers and w,
c, d, or x for all other fingers, according to its classification as
defined in figure 354. These symbols are used for subclassification
purposes only and are brought up into the classification formula
directly above the subsecondary in their respective positions, the
right hand being the numerator, the left hand being the denominator.

SPECIAL LOOP EXTENSION: In the all-loop group

(1R-U)
------
(1R-U),

the following special loop extension may be used, utilizing the ridge
counts in fingers Nos. 2, 3, 4, 7, 8, 9, and, if necessary, No. 10:

_Ridge Counts_ _Value_

1 to 4, inclusive 1
5 to 8, inclusive 2
9 to 12, inclusive 3
13 to 16, inclusive 4
17 to 20, inclusive 5
21 to 24, inclusive 6
25 and over 7

The resulting values in this extension are brought up into the
classification formula directly above the subsecondary in their
respective positions, the right hand being the numerator, the left
hand being the denominator.

In addition to the extensions already mentioned, fingerprint groups
may be divided into male and female, and by age (either by year or by
arbitrarily setting an age limit, beyond which a print bearing such an
age would be filed separately in a "Reference" or a "Presumptive Dead"
file).

In the files of the Federal Bureau of Investigation, all prints
bearing an age of 55 through 74 are filed in the "Reference" group and
all prints bearing an age of 75 years or more are filed in the
"Presumptive Dead" file. Persons 75 years of age or older, in regard
to crime, may be considered as generally inactive and thus are filed
as "Presumptive Dead." Such a group provides for removing from the
other files the cards concerning those of whom no notice is ever
received as to death.

A separate file should be main