08 TREUBIA VOL. Il, 1. 
other hand we should not lose the hope that at least the most conspicuous 
and best recognizable kinds of eggs may be known and that the number 
known may gradually increase. 
During the first year of my stay at Batavia | made a cruise every 
two months with the investigation vessel, the Government steamer „Brak”, 
and visited a number of fixed stations along the North coast of Java and 
Madura. These stations have been indicated on the chart on page 106. 
At each of these stations a vertical haul was made with a large vertical 
egg-net (length 4 m., diameter of the opening 130 cm., planktongauze nr. 3 
of the Schweizerische Seidengazefabrik A. G. THAL), while at the same 
time observations on the temperature and the salinity of the sea-water 
were carried on. The catches were conserved in seawater-formaldehyd 
1°/, and at home the eggs and larvae were picked out Thus a consi- 
derable material was gathered. Every station had been visited six times 
and in comparing the results of the six cruises one might get a provisional 
idea of the seasonal and local distribution of certain eggs, even if he did 
not know to which species they belong. Since, however, conclusions in 
this direction cannot be drawn from the results of one year only, | continued 
these observations during the second year in the same way, but limiting 
the number of stations visited by leaving out P—U. 
The time thus spared was dedicated to investigations of another kind, 
viz. to attempts to trace the development of pelagic eggs and of the larvae 
hatched from them. To this end horizontal hauls along the surface were 
made with the above mentioned egg-net. The eggs were immediately 
picked out from these catches. To this end the catch, containing much 
plankton of course, was put into a flat glass vessel and this placed on a 
piece of black paper. With the aid of a magnifier and a pipette the eggs 
were then isolated in drinking glasses with fresh seawater. 
As a rule we find in such a catch the number of egg kinds limited, 
but of every kind more than one and often even a pretty considerable 
number of specimens, and all these in the same stage of development. This 
favourable circumstance is evidently due to the fact that the fishes spawn in 
shoals and all at the same time. With several fishes spawning seems to be 
restricted to definite hours of the day. The European anchovy spawns during the 
night and similar oblong eggs which are common in the Java sea and evidently 
belong to related species were always found in sucha stage of development 
that we may conclude that these fishes likewise spawn during the night. 
When thus a number of eggs of a certain kind and all in the same 
stage of development had been isolated in a drinking glass, the hatching 
was observed and the larvae brought up as far as possible. From time to 
time one or afew were fixed in seawater-formaldehyd 4°/,. The development 
proceeds much faster than in European waters. In the North Sea the 
average temperature of the water is about 10°, in the Java Sea it is certainly 
not less than 28°. While in the North Sea the hatching of the eggs takes 
