SUNIER: The Laboratory for Marine Investigations. 147 



At the places where the fish I was studying were caught, data regar- 

 ding temperature and salinity, as well as plankton samples, were collected 

 always at various depths. 



Further, Dr. H. C. Delsman, who has been attached to the Labora- 

 tory as zoological assistant since June 1919, is engaged on the study of 

 pelagic fish eggs and larvae of the Java Sea about which, practically 

 speaking, nothing was known previously. 



Nov^, the number of fish species living in the Java Sea is much greater 

 than the number of those fish species met with in the great fishing grounds 

 of the North-West European seas. 



Besides which, in the latter seas, each fish species has its own spawning 

 season which is not the case in our Indian waters or at any rate to a 

 much lesser degree. 



For these reasons it is to be questioned whether it will ever be possible 

 to identify all the pelagic fish eggs that occur in the Java Sea, 



Finally the circumstances induced me to undertake in 1918 and 1919 

 an investigation into the biology of the sea fish ponds lying along the 

 coast of Batavia, and in which Clianos chanos (FORSK-) are reared. 



in these ponds large floating masses of algae or conglomerates of 

 algae and higher submerged aquatic plants, reaching up to just beneath 

 the water surface, develop spontaneously. 

 Chanos chanos (FORSK.) feeds on these algae and higher aquatic plants. 



In connection with this the Batavia sea fish ponds produce enormous 

 quantities of the most dangerous of our malaria-carrying mosquitos, 

 Myzomyia Indlowi THEOBALD, and this in spite of the presence of great 

 numbers of Hoptochilus panchax (HAM. BUCH.) which have a certain 

 renown as larvae destroyers. 



Ludlowi mosquitos are, however, only found when the salinity of the 

 pond water does not rise much above 30°/oo; at salinities above 40 7oo 

 they are not produced, although even at much higher salinities large quan- 

 tities of Myzomyia rossii Giles, a species very closely allied to ludlowi, 

 but as good as harmless, are still produced. 



The highest salinity of many examinations concerning the water of 

 the Batavia sea fish ponds containing Chanos chanos (FORSK.) amounted 

 to 84.6o/oo. 



During the West Monsoon the water of the Batavia marine fish ponds 

 can be, on the contrary, almost entirely fresh. 



The results of the investigations undertaken by the Laboratory are 

 published in "Treubia", Recueil de Travaux Zoologiques, Hydrobiologiques 

 et Océanographiques, issued by '"s LANDS Plantentuin" at Buitenzorg. 



The latter institution embraces all purely scientific establishments 

 belonging to the Department of Agriculture, Industry and Commerce of 

 the Netherlands East Indies. Accordingly, 's LANDS PLANTENTUIN also 

 includes the Laboratory for Marine Investigations at Batavia. 



