J. W. Jenkinson 
157 
First Fid-niw and Satiitlal Plane. 
45 - o + 45 
S CO 
Fig. 7. Kegression Scheme constructed from Table VI. The dots have 
the same significance as in Fig. 6. 
III. Plane of Symmetry and First Furrow. 
As Table VII. shows, the first furrow tends to lie either in or at right angles to 
the plane of symmetry, though the former predominates. In Fig. 8 I have 
accordingly divided the frequency polygon into two parts, one distributed about 
TABLE VII. 
Plane 
of Symmetry 
and First Furrow. 
Groups 
of 10°. 
Variation about 0°. 
Variation 
about 90°. 
Class 
Frequency 
Class 
Frequency 
- 45— 36 
8 
+46— 55 
17 
35— 26 
17 
56— 65 
14 
25— 16 
21 
66— 75 
13 
15— 6 
26 
76— 85 
17 
5—+ 5 
98 
86 86 
44 
+ 6— 15 
26 
-85— 76 
23 
16— 25 
16 
75— 66 
9 
26— 35 
18 
65— 56 
15 
36— 45 
13 
55— 46 
16 
243 
168 
Variation about 0° 
i/= -53° ± -853 
o- =18-70°+ -603 
Variation about 90° 
J/=90-17°±l-212 
o- =23-29°+ -857. 
0°, the other about 90°. This alternative of two " predilection " directions, to 
borrow a phrase of Roux's, for the first furrow to choose from, completely throws 
out the correlation (Table VIII. and Fig. 10) ; but if the range from — 4.5° to 
+ 4.5° only be considered (Table IX.) the value of p rises to "271 + 'OSS. In the 
" scatter " diagram (Fig. 9), in which each instance is separately recorded, the 
coincidence of the two planes is very well shown by the crowding of the dots 
along the diagonal. 
