SEX DETERMINATION IN DINOPHILTJS GYROCILIATUS. 345 
but still remains very sticky on the surface, so that if 
it is touched with a needle it adheres so firmly to both 
needle and the bottom of the dish that it usually tears 
apart and the eggs in the interior are destroyed. The eggs 
themselves are also difficult to handle in the living state, 
as they stick with great tenacity to the inside of pipettes and 
sides of needles, and cannot be detached without breaking. I 
have been reduced to handling them when stuck to small 
pieces of tissue paper. Small pieces of paper are cut, and 
then with the aid of fine forceps the egg-capsule is scooped 
up, the capsule adhering firmly to the paper ; then the paper 
with the capsule may be readily transferred from one dish to 
another, or into the fixing fluid. 
The two kinds of eggs, male and female, are laid together 
(fig. 57) in a fairly constant ratio of a little more than two 
female eggs to one male, and this ratio does not appreciably 
change during the different seasons of the year. I have 
made, however, no special observations to test this point. 
The following table gives the number of eggs , male and 
female, counted in capsules collected at different seasons of 
the year : 
Table showing the Proportion of Male to Female 
Eggs in Forty Capsules 
collected 
at Di 
iff ere 
Seasons of tli 
e Year. 
Spring. 
Summer. 
1 Capsule 2 <$ 
4 ? 
11 
Capsule 
2 <? 
5 ? 
2 1 „ 
o 
u yy 
12 
)) 
9 
^ }) 
8 „ 
3 „ 2 „ 
6 „ 
13 
}) 
4 „ 
8 „ 
4 2 
8 „ 
14 
)) 
1 „ 
9 
^ }) 
5 9 
6 „ 
15 
9 
6 „ 
6 2 „ 
4 „ . 
16 
}) 
o 
3 „ 
6 „ 
7 „ 4 „ 
10 „ . 
17 
}) 
9 
" )) 
5 „ 
8 2 „ 
o , , 
18 
}} 
i 
3 „ 
9 „ 2 „ 
8 „ 
19 
>} 
3 „ 
8 „ 
10 „ 1 „ 
3 „ . 
20 
>) 
9 
u )) 
6 „ 
Total 20 
56 ? 
Total 
22 4 
57 ¥ 
