OS 
VARIATION IN BANDING. 
Fig. 100. — IIcU.x newornlh L., 
formula 
Truro, Cornwall, 
Collected by Mr. J. 11. James, A.R.I.C 
Fig. 200 . — Helix nemoralis F., 
formula 12 'U‘jIo. 
allowing- the groninl tint to he visible along the sntnre and in the 
ninhilical region (see fig. 100), this is 
shown by enclosing the whole of the 
five figures within the parentheses, 
the formula being (12345). 
Supernumerary or e.xtra hands may 
also apparently he developed, so that 
a specimen may seem to have si.\, 
seven, or more hands, hnt these additions to the normal five, are 
invariably owing not to a real increase in their number, but to the 
separation or splitting np of one or more 
of those normally existent, and con- 
sequently these extra or sujiernumerary 
hands are always finer and thinner than 
the normal undivided hand would have 
been. 'I'liis splitting up or sub-division of the hands can be indicated 
in the formula by the use of a smaller figure placed in such a position 
as to represent the situation actually oc- 
cupied relatively to the regular banding 
by the slender split-off handlet : thus, 
if the third hand he .split about equally, 
it .should be indicated by r2'3.'545 (see 
iiG. /AA.r 200), or if the split-off handlet is 
much n.arrower than the remaining portion of the hand from which it 
has been separated and is placed beneath it, the formida .should be 
I2.‘5"45 (see fig. 201), but if the handlet 
he ])lacod above the haml it is derived 
from, the smaller figure, by the position 
it occupies, ecpially servos to indicate its 
])o.sition and character, the formula being 
12 15 (see fig. 202). 
In those cases where, from their equi-distant position, it is difficult 
or impossible to decide with certainty 
from which of the normal bands the extra 
'A liandlets have been dei'ived or .split off, 
so that the appropriate numerals cannot 
he used to indicate their ])osition and 
Fig. 20.T — //i*//> iiciiroraiis L., • • n • i • j i 
formula i2;{xi.), OFigiii, theii a small x is used instead 
of a nnmher in the pro])er position to indicate their presence, thus 
Fig. 202 . — Helix ncuioyalis L., 
formula 12-!315, 
