SUNIER: Marine fish-ponds of Batavia. 249 
virtually impossible that the eggs should have been laid or rather produced 
outside the body before the afternoon of the previous day. 
These eggs, therefore fertilized early on the morning of November 11th 
1919, I laid apart in a glass dish with pond-water and Chaetomorpha-threads, 
as was described above for the artificially 
fertilized eggs of Haplochilus panchax. On the 
same November 11th 1919, fig. 23 was drawn 
from two of these eggs. The next morning, 
i.e. a little more than 24 hours after fertili- 
zation, these two eggs presented the appear- 
ance of fig. 24. As is proved by this latter 
drawing the oil-globules had at that time Fig. 26. The eggs of fig. 23—25, 
united into one bigger globule. Thefigures25, lite more than 3 times 24 hours 
26, 27, 28, 29 and 30, were drawn 2, 3, 4, 5, 
6, 7 and 8 times 24 hours respectively after fertilization, after the same two eggs. 
At 8 o’clock in the morning of November 21st, it finally appeared 
that between that moment and 1 p.m. on the 
previous day, i.e. more than 9 but not more than 
10 X 24 hours after fertilization, the first two 
of these eggs had come out. By an accident 
the other unhatched eggs were lost that day. 
Two months before, September 17th 1919, 
| had however also taken twenty eggs from 
Fig. 27. The eggs of fig. 23-26 the genital opening of a female Haplochilus 
a little more than 4 times 24 javanicus, and placed them in a glass dish 
hours after fertilization. X 18. with Chaetomorpha-threads. From the stage: 
of development they had reached they had doubtless been fertilized 
early that morning. All these eggs disclosed between about 10 and 13 
times 24 hours after fertilization. 
From the above it is deducible that the devel- 
opment within the egg-capsule lasts a little longer 
for Haplochilus javanicus than for Haplochilus 
panchax, say about 24 hours on an average. 
In conclusion | have another peculiarity 
to mention which was observed in the embryos 
still enclosed in the egg-capsule of Haplochilus 
panchax. While studying through a binocular 
microscope a kepala timah egg found in a tuft Fig. 28. The eggs of fig. 23—27 
of Chaetomorpha brought from the Batavia à little more than 6 times 24 
2 , hours after fertilization. X 18. 
empangs, I noticed that, on my accidentally 
pushing against the table on which stood the binocular microscope, the 
heart of the already advanced embryo contained in the egg-capsule suddenly 
stopped and did not begin to beat again till 10 or 20 seconds later, very 
slowly at first but gradually more quickly. 
