AAE SUNIER: Marine fish-ponds of Batavia. 235 
larvae is still found in the alimentary canal of the kepala timah when the 
rest of the body of the larva is already entirely digested. 
The Nereidae I found in the fore-part of the alimentary canal ') of a 
large number of kepala timah which had been caught (August 5th 1920) 
in one and the same pond near Luar Batang. The fore-part of the alimen- 
tary canal of these kepala timah was crammed full of the Nereidae to such 
an extent that the little fish all displayed strongly swollen bellies, so that 
at first I thought they were iil. In addition to the Nereidae mentioned the 
fore-part of the alimentary canal of these kepala timah also contained some 
Gammaridea, 
From the above list it is certainly clear that the kepala timah in the 
empangs feeds on all possible kinds of little and sometimes also somewhat 
larger (Nereidae) animals living in the ponds, and even on terrestrial 
animals which like the above-mentioned ants happen to drop into the 
pond-water. | 
Judging from the conduct of the kepala timah kept alive in aquaria, 
I can. further entirely concur, as concerns the Haplochilus panchax, with 
the statement of SEYMOUR SEWELL and CHAUDHURI (3°) that the Hap- 
lochilus species feed exclusively on live organisms. 
Although the kepala timah is fond of devouring mosquito-larvae and 
-pupae and also occurs in countless numbers in the fish-ponds, yet the 
empangs teem with mosquito-larvae and -pupae in those places where the 
submerged vegetation reaches the surface of the water and also among 
the overhanging plants touching the water along the edges of the ponds. 
This experience entirely confirms that gained elsewhere, summarized 
in MENSE’s Handbook (°°) in the following sentence, introducing the dis- 
cussion of the significance of fish-species devouring mosquito-larvae and 
-pupae as a malaria prophylacticum: “Fische scheinen für manche Gewässer 
eine ziemliche Bedeutung zu gewinnen, aber nur, wenn sich kein starker 
Pflanzenwuchs darin befindet und die Ufer steil ansteigen, da anderenfalls 
die Larven zuviel Schutz finden.” 
‘For a further discussion of this question the reader is referred to 
Chapter VII. 
In his Atlas Ichthyologique BLEEKER (*) says that Haplochilus panchax 
occurs “in fluviis et lacubus”. 
MAX WEBER (!!) in his table concerning the occurrence in the 
Netherlands East Indian Archipelago of genuine fresh-water fishes, and 
of sea- -and brackish-water fishes also to be met with in fresh water, 
mentions Haplochilus panchax for the fresh water of Java, Sumatra and 
Borneo. . 
WILSON (#7) only mentions Haplochilus species among the mosquito 
destroyers in fresh water; for salt and brackish waters he only names 
1) In the fore-part of the alimentary canal of Cyprinodontidae a differentiation 
into oesophagus and stomach has not yet developed. 
