228 TREUBIA VOL. II, 2—4. 
but thinner’, This may be the same word as GRONEMAN (**) means. I have 
not, however, succeeded in finding out the meaning of tjéto or tjétaq. 
The little spot on the head of the kepala timah, which is more or less 
lozenge-shaped, with a white metallic shine, or sometimes dull like white 
chalk, is situated above the posterior part of the brain (cf. fig. 15) and it 
Fig. 15. Haplochilus panchax (HAM. BUCH.) from the Batavia 
empangs, seen from the dorsal side. X 2!/5. 
can be obscured by pigment cells expanding in the dark and covering over 
the spot. It has already been described by MIEHE, as also stated in the 
latest edition of BREHM’s Tierleben (7°). | 
According to BREHM, MIEHE says that the pigment cells above the 
little spot which are capable of contraction and expansion only react upon 
light. I have not made any experiments on this. But I have repeatedly seen 
how the little spot darkened suddenly when the kepala timah was taken out 
of the water with a little aquarium net or with a glass dish. In briskly live 
little fishes, just removed from the water the spot is accordingly always 
quite obscured even in full daylight. If the fish is placed in the water again 
the little spot very quickly grows white and shining again. The same thing 
happens if care is taken to prevent any change in the exposure to the light. 
If a kepala timah whose spot is shining brightly is placed between the glass 
wall of an aquarium and a glass dish, the spot dims at once upon the 
kepala timah being raised along the glass wall by means of the dish until 
the animal comes to lie dry. On lowering the dish again so as to bring 
the little fish under water again the spot is seen to turn a clear white 
again within one or two seconds. Also when the kepala timah made quick 
sudden movements I sometimes saw the little spot brighten suddenly. 
BREHM, or rather STECHE (*) in reporting MIEHE’s observations 
speaks of the “blue” Haplochilus panchax. Now it is true that in a live 
kepala timah recently drawn from the water the lower surface of 
the body on either side of the ventral fins and of the anal fin mostly 
displays a light-blue or light-violet metallic hue. Also on the gill-covers 
and behind them, as far as the implantation of the pectoral fins, besides 
green colours there are also pale-blue or lilac metallic hues to be seen. 
But it will not do to call the animal itself blue. The dominating colour is 
green-brown or a brownish green, especially on the dorsal side. BLEEKER (*) 
7 
