210 TREUBIA VOL. II, 2—4. 
at all, but it held a large number, viz. as many as 4000 rather young 
bandeng, which as Mr. Görs said were feeding on “mud”. Under these 
circumstances however, the animals could not thrive, and they were 
therefore shortly to be transferred to one of the more inland ponds 
in which the “lumut” had been allowed to develop quietly. The entire 
absence of “lumut” at that moment from pond F of Map II, according to 
Mr. Görs Jr. was chiefly owing to the fact that this pond contained so 
much bandeng that all the “lumut” developing there was immediately 
consumed. 
On April 3rd 1918, I saw once more not only in a pond of Mr. Görs’s 
near Muara Karang, but also in a pond near Heemraad, containing a great 
many bandeng, numerous pieces of Ruppia rostellata floating about with 
the leaves eaten away. On that same day I could further examine again the 
still undigested contents of the stomachs of two bandeng which I saw 
caught in a pond near Muara Karang, which pond had been leased by 
the Chinese proprietor to another Chinese fish-farmer. The latter, I was 
informed by his labourers, did not leave the “lumut” time to develop 
again in a pond cleared of fish, but turned in new bandeng as soon as 
possible. The gizzards of these bandeng were strongly contracted and 
practically empty, containing only a few Rotatoria, a minute water-bug and 
some very few Oscillatoria-filaments. 
Towards the end of June I came upon the submerged vegetation 
represented in photo 4, Plate IX, in pond G of Map II. It reached up to 
just beneath the surface of the water and consisted of Chaetomorpha- 
threads coated more or less with Chamaesiphonaceae and Chlamidobacte- 
riaceae, of Ruppia rostellata KOCH, and of Najas falciculata R. BR., all this 
overgrown by Oscillatoria and other Hormogoneae, by Gloeocapsa (red- 
coloured, cf. also Chapter IV), etc.. 
As may be seen in the right-hand lower corner of photo 4, Plate IX, 
the water along the margin of the pond was open; the submerged vege- 
tation occupying the shallower (cf. page 165) central part of the pond. 
The rounded bights of open water along the margin of the submerged 
vegetation are due to the bandeng having eaten away parts of that vegetation 
in those places. 
This I could observe on June 27th and 29th, 1918, when I saw how 
in the round bights just mentioned several of the many bandeng swimming 
about in the marginal ditch (cf. page 165) came ever and anon to 
eat of the submerged vegetation. The animals with their mouths close 
beneath the surface of the water then took a mouthful of the edge of the 
submerged vegetation, sometimes loosening it with a few jerks. In this 
same pond I afterwards saw on three more occasions, viz. on July 16th, 
July 30th and September 6th a number of bandeng eating together of the 
submerged vegetation. 
On June 29th 1918, in a pond belonging to Ang Sun Hian near 
zussie a Ml 
