J. W. Jbnkinson 
185 
TABLE XXXIV. 
Sperm Entrance Meridian and Direction of " PressiLre." 
Eggs close. Axes horizontal. 
Difference between angles and their Supplements. 
a. Regarded. 
h. Disregarded. 
+ 180—165 
7 
- 0— 15 
0 
- 0—15 
7 
165—150 
7 
15— 30 
0 
15—30 
7 
150—135 
10 
30— 45 
0 
30—45 
10 
135—120 
15 
45— 60 
0 
45—60 
15 
120—105 
8 
60— 75 
6 
60—75 
14 
105— 90 
9 
75— 90 
8 
75—90 
17 
90— 75 
3 
90-105 
10 
+ 90—75 
13 
75— 60 
3 
105—120 
11 
75—60 
14 
60— 4S 
2 
120—135 
8 
60—45 
10 
1,5— 30 
1 
135—150 
6 
45—30 
7 
30— 15 
1 
150—165 
5 
30—15 
6 
15— 0 
2 
165—180 
4 
15-0 
6 
Total 
68 
Total 
58 
Total 
126 
M=+l]8-46°: 
±3-18 
-114-32° + 2 
•68 
- 85-83° ± 
2-65 
0-= 38-94°±2-25 30-27°±l-90 44-13°±l-87 
But however that may be, it is clear that spermatozoa enter mainly where the 
eggs in the rows are in contact. This must be attributed, I think, to their congre- 
gating in greater numbers in these places, and this in turn to either capillarity, or 
to some chemotactic stimulus exerted in excess at these points by the jelly. It 
cannot, I believe, be assigned to any phototactic stimulus, since it is not observable 
in the case of the spaced eggs. 
We have already established the facts that the First Furrow tends to place itself 
parallel to the length of the slide, and that it very frequently includes the point of 
entrance of the sperm. The position of the First Furrow in compressed eggs 
would then appear not to be determined by the pressure, which is slight, (certainly 
less than that used in ordinary pressure experiments), but to be due simply to 
the fact that the sperm prefers to enter in between the eggs in the rows. 
There is no reason that I can see for supposing that gravity, which is not 
eliminated in this experiment, has any share in the result. 
(7) The inclination of the Sperm-radius to the Egg-axis, or the angle sub- 
tended at the centre of the circle by the distance of the point of entrance from the 
animal pole. This angle is never greater than 90°. 
There is naturally no distinction between positive and negative angles. 
I. When the eggs are close, their axes horizontal (Table XXXV. I.), the 
mean value of this angle is 40'65°, that is, the sperm under these conditions usually 
enters about half-way between the animal pole and the equator. These eggs it 
Biometrika vii 24 
