156 Symmetrii of Efia and Sijmmetry of Embryo in the Frog 
The correlation table (Table V.), constructed by taking the first furrow as 
a fixed line and correlating the angles made with it by the sagittal plane and the 
plane of symmetry, and the regression scheme (Fig. 6) bring out the result in 
another way. 
First Furroio and Sagittal Plane. 
90 ^ , ~T . . ? . . "i" . • 
"o> ■ 
S 
o -■ 
c 
p 
Fig. 6. Kegression Scheme of the mean values of angles between I'irst i'urrow and Plane of Symmetry 
for each class of angle between First Furrow and Sagittal Plane. Constructed from Table V. 
The correlation is obviously spoilt by those cases in which the first furrow is 
at right angles to the plane of symmetry ; but b}^ taking the 36 central squares of 
the table only (Table VI. and Fig. 7), the value of p may be increased to 
"439 ± "032. By taking the six middle arrays only, it may be increased still 
further to -477 ± -028. 
TABLE VI. 
Constructed from the 36 Central Squares of Table V. 
First Furrow and Sagittal Plane. 
oj 45 — o + 45 Totals 
13 
19 
75 
54 
22 
13 
45 o 45 
Totals 
19 
20 
50 
47 
42 
18 
Means 
-1-0 
-•7 
- -06 
+ •21 
+ •41 
+ •9 
p=^439±^032. 
^ ^ + 
I a ° 
^ o 
1 
2 
5 
5 
1 
5 
4 
7 
2 
3 
4 
20 
25 
14 
9 
5 
9 
15 
11 
13 
1 
4 
6 
7 
4 
1 
6 
1 
2 
1 
2 
1 
