SUNIER: Marine fish-ponds of Batavia. 247 
in a low glass dish with water, placing them among a few fresh Chaeto- 
morpha-threads. This glass dish was covered over with a glass cover and 
the whole was then placed well in the light, but not ín the sunshine. 
Not all artificially fertilized eggs could be made to hatch in this way. 
This would however seem to me to be due chiefly to the circumstance 
that by squeezing a female fish it is also made to yield immature ova. 
To quote an example from my notes, | find that out of 23 Haplochilus 
panchax-eggs artificially fertilized in the above manner on August 23rd 
1919, eleven did not develop, and 12 did. Of these latter 12 eggs artifi- 
cially fertilized on August 19th 1919, between 11.30 and 11.40 a.m. 
there came out: 
8 between 27 VIII 19, 1 p.m. and 28 VIII ’19, 9.45 a. m., 
i.e. in 8 to 9 times 24 hours after fertilization ; 
2 between 28 VIII ’19, 1 p.m. and 29 VIII 719, 8 a. m, 
je. in 9 to 10 times 24 hours after fertilization ; 
1 between 29 VIII ’19, 1 p.m. and 30 VIII ’19, 7.50 a. m., 
i.e. in 10 to 11 times 24 hours after fertilization ; 
1 between 1 IX 719, 1 p.m. and 2 IX 719, 7.50 a. m., 
i.e. in 13 to 14 times 24 hours after fertilization. 
Furthermore I found in the morning of January 27th 1920 in an 
aquarium in which mature kepala timah were living, 4 eggs attached to 
Chaetomorpha-threads. From the stage of development they were in (see 
below) it appeared that they had been fertilized a few hours previously. 
Of these 4 eggs fertilised in the morning of January 27th 1920: 
2 came out between 4 II ’20, 1 p.m. and 5 II ’20, 8 a. m., 
i.e. between 8 and 9 times 24 hours after fertilization; 
and 1 came out between 5 II ’20, 1 p.m. and 6 II ’20, 8 a.m., 
i.e. between 9 and 10 times 24 hours after fertilization. 
Of the 4th egg the embryo died between 5 II ’20, 1 p.m, and 6 II ’20, 
8 a.m. within the egg-capsule. 
From the above it appears that under the circumstances described by 
me, most of the young Haplochilus panchax come out of the egg-capsule 
more than 8 and less than 9 times 24 hours after fertilization. In the above 
mentioned cases this never took place earlier, but sometimes up to 5 times 
24 hours later. 
A young kepala timah just out of the egg-capsule is represented 
TMS 31: 
When I continued to watch the kepala timah eggs artificially fertilized 
in the above-described manner, under the binocular microscope, from the 
beginning, I saw in the first place, how after the eggs had just been 
impregnated and got into the water a space began to form in the well-known 
way between the cosperm and the egg-capsule, whilst the formative yolk 
began to protrude from the globular nutritive yolk, in the shape ofa little 
prominence or rounded cap flattened at the outer surface. In this cap of 
