J, W. Jenkinson 
1G3 
the action of the light. The dorsal lip would then appear as readily on the side 
of the egg turned towards as on that turned away from the light. The dorsal 
lip is formed in a region of active cell-division, and cell-division may probably be 
promoted by light as well as it is known to be by heat. I had previously found, 
as noted in the publication referred to above, that the Sagittal Plane will place 
itself either in or at right angles to the direction of a strong artificial light. 
TABLE XVI. 
Sagittal Plane. 
I. 
II. 
III. 
IV. 
Eggs close 
Eggs 
close 
Eggs spaced 
Eggs spaced 
Axes horizontal 
Axes vertical 
Axes horizontal 
Axes vertical 
Angle 
A 
B 
A 
B 
A 
B 
Darkness 
Light from 
Liiglit from 
Light ? 
Li"ht from 
Li'^lit from 
^'^+90°°™ 
+ 90° 
0° 
\ 90° 
°+ 90° 
- 180 -165 
6 
0 
29 
4 
1 
4 
32 
165—150 
9 
1 
21 
3 
3 
2 
28 
150—135 
4 
33 
4 
2 
2 
25 
135—120 
11 
0 
38 
7 
3 
23 
1-20—105 
14 
2 
30 
4 
6 
17 
105—90 
35 
3 
48 
6 
6 
6 
20 
90—75 
55 
1 
50 
8 
12 
6 
26 
75—60 
67 
5 
40 
1 
15 
3 
11 
60—45 
53 
12 
17 
5 
5 
1 
6 
45-30 
48 
7 
28 
3 
14 
4 
12 
30 — 15 
57 
9 
16 
9 
3 
15—0 
56 
10 
23 
4 
10 
4 
20 
+ 0-15 
46 
15 
21 
1 
13 
2 
14 
15—30 
43 
9 
16 
4 
10 
3 
12 
30—45 
43 
13 
22 
6 
3 
16 
45—60 
49 
22 
6 
12 
5 
8 
60—75 
64 
10 
24 
17 
9 
19 
75—90 
65 
3 
28 
12 
9 
3 
14 
90—105 
47 
2 
30 
14 
8 
12 
105—120 
31 
1 
31 
11 
8 
0 
17 
120—135 
17 
1 
27 
6 
6 
2 
27 
135—150 
9 
0 
26 
9 
6 
24 
150—165 
0 
29 
9 
4 
5 
21 
165—180 
6 
1 
21 
6 
6 
3 
31 
Total 
114 
M 
1 -.32° ±1-81 
a 
*28-64°±l-28 
The direction of pressure is from 90° to 90°. The gravitation symmetry plane from 0° to 180°, 
the white pole being turned towards 0°. 
* Calculated on groups of 30°. 
21—2 
