SUNIER: Marine fish-ponds of Batavia. 273 
We may now proceed to a closer consideration of the Tables V to XI. 
From Table VII (A and B) it is manifest that the rossti-production of 
the empangs observed by us, whose magnitude is from the nature of the case 
determined by the conjuncture of a great many conditions, was considerably 
higher when the salinities were between 40 and 846°/,, than when the 
salinities were below 40°/,,, so that to put it in the mildest form, there is no 
ground whatever for concluding that the increased salinities should have 
an unfavourable influence on the production of rossii. Contrarily the 
ludlowi-productions of the same milieu at salinities above 25°/,, were 
considerably smalier than when the salinity was lower. Moreover the catches 
by mosquito nets never yielded a /ud/owi mosquito when salinities exceed- 
aol ADS aes 
Concerning this latter question a further comparison of the Tables VII, 
V and IV teaches us that the catches by means of mosquito-nets effected 
when salinities ranged between 40 and 49.9°/,,, for which totally 145 nets 
were set in 24 different places in the Batavia empangs, yielded 3082 ') 
female rossii, but only 4!) /udlowi females, of which 4 /zdlowi females 
3 were caught when a salinity of 40.0°/,, was marked and 1 when the 
salinity was 42.8 °/,. 
Furthermore a comparison of Tables VII, V and IV shows that at 
salinities upwards of 42.8°/,, the catches with mosquito- nets made in 24 
different places in the marine fish- ponds near Batavia, for which totally 
about?) 144 mosquito nets were set, yielded 4211 rossii females as against 
no dudlowi females at all. 
I have thought it desirable just to mention these original, not yet 
reduced figures from Table IV because they show that my conclusions 
derived from the captures in mosquito-nets are based upon an ample 
material of facts. 
I have just said that it appears clearly from Table VII (B) that there 
is no ground for concluding to an unfavourable influence of the increase 
of the salinity on the production of rossii. On the other hand I am 
certainly not disposed to ascribe the very high figures for the rossü- 
production at salinities between 50 and 69.9 °/,, to any favourable influence 
of those salinities as such. As we shall see further down we must assume 
that this great production of rossii, occurring in conjunction with high 
salinities, was due to the fact that at the times and in the places where 
1) It may probably be superfluous to point out that with these figures 3082 and 
4, correspond the figures 4902 and 5 in Table VII. For Table VII was derived from 
Table V, in which latter table the net-catches of Table IV are all expressed per 10 M? 
(and per night), The figures mentioned here, scil. 145 nets, 3082 rossii females and 4 
ludlowi females are deduced from the figures in Table IV concerning the catches in 
mosquito-nets, not yet reduced to the units of Table V. 
2) “about 144”, because (cf. Table IV) at the time it was omitted to note down 
how many nets had been set in the ponds near Jaagpad on November 16th, 17th, 20th 
and 21st. There were probably six or at all events more than 4 nets each time. | have 
counted 5 mosquito-nets for each of these four catches. ; 
