206 TREUBIA VOL. II, 2—4. 
Mr. Görs’s fry-ponds, the water in which then had a salinity of 62.8 °/,,, 
I found a school of bandeng-fry which had been brought the day 
before from Tjemara (Krawang coast) and had been put into this small fry- 
pond. 
On October 28th 1918, i.e. 13 days later, this same bandeng-fry was 
living in water possessing a salinity of 77.6°/, On the other hand on 
-May 14th 1918 | met with bandeng-fry which on arrival a week before 
had been lodged in a little pond whose water on that 14th of May hada 
salinity of 20.3 °/ go. 
Regarding the salinity of the water in fry-ponds the reader is further 
referred to Table I sub C and C’. However the fry-pond whose water 
on October 20th and November 4th 1919 showed salinities of respectively 
81.0 °/5, and 93.2°/,,, according to my diary contained no bandeng on 
both dates mentioned. 
When water was flowing into an: empang either from a feeding and 
draining canal or from another pond, | often observed in the bandeng a 
strong inclination to swim against the current. Thus on June 15th 1916 
I watched large numbers of young bandeng, from five to six centimetres 
long, remove spontaneously against a very strong current from one pond 
to an other, through a connecting-channel perhaps three decimetres wide 
and not yet a metre long in which the water stood about ten centimetres 
high. In doing this the young bandeng frequently jumped out of the 
water against the direction of the current. 
On September 24th 1918, | saw large numbers of young bandeng 
from ten to twelve centimetres long thronging before the entrance to a 
similar connecting-channel, which however was in this case barricaded 
with a trellis-work (kereh=split bamboo slats, tied together with split 
rattan). They tumbled over one another and frequently jumped into the 
air in their fruitless attempts at swimming up current. Now in this instance 
the water in the lower pond had a salinity of 52.2°/,,, whereas that in 
the upper pond had a salinity of 46.2°/,,, so that the question necessarily 
arose whether it was perhaps chiefly this difference in the salinities which 
induced the strong impulse to swim up current. 
But on November 18th 1918 it became evident that a considerable 
difference in the salinities up-stream and down-stream is not a necessary 
condition for inducing in the bandeng a vehement impulse to swim against 
a current. I then came to a pond to which water was just being admitted. 
At a distance of about 20 yards from the little sluice-gate through which 
the water came flowing in, the pond-water had a salinity of 33 °/,,. Above 
the little sluice-gate, i.e. outside the pond, in the feeding channel, the 
salinity amounted to 32.65 °/oo. The difference was therefore only 0.35 0/4. 
Access to the sluice-gate was barred to the bandeng from the side of the 
pond by a framed bamboo trellis-work (cf. photo 1, Plate VI). 
A crowd of fairly large bandeng + 9 months old, which were destined 
