FISH EGGS AND LARVAE FROM THE JAVA SEA 
by 
Dr. H. C. DELSMAN. 
Laboratorium voor het onderzoek der zee, Batavia. 
1. Fistularia serrata Cuv. 
with 8 figures and a chart. 
Very little is known on the propagation and development of Indian 
sea-fishes. Therefore, when appointed assistant at the Laboratory for the 
Investigation of the Sea at Batavia, | was glad that the head, Dr. SUNIER, 
offered to me the opportunity to study this subject The eggs and larvae 
of the principal kinds of fishes occurring in European seas are now pretty 
well known. Since, in the year 1864, Sars discovered the first pelagic 
fish eggs, viz. those of the cod, our knowledge of this subject has rapidly 
increased, as may be seen from the compendium given in 1905 and 1909 
by Professor EHRENBAUM in “Nordisches Plankton’. Like those of the cod, 
the eggs of far the majority of marine fishes in Europe are small, trans- 
parent globules floating about freely near the surface of the sea. The 
number of marine species with demersal eggs or which fix their fry to 
stones or weeds, as is the rule with fresh-water fishes, is only very restricted. 
To distinguish the different kinds of pelagic fish egg floating 
promiscuously in the sea is by no means an easy task and often even 
impossible. Sometimes peculiarities of the egg-membrane or of the yolk 
or e.g. an elongated shape of the ege may help us. But these cases are 
relatively exceptional. The diameter of the egg and the presence or absence 
of oil-globules are, as a rule, the main characteristics on which to found 
the determination. The diameter, however, is subject to a certain variability 
and thus it often occurs that different kinds of eggs which do not differ 
much in diameter can not satisfactorily be distinguished and separated in 
this way. This is the case even in European seas, where the number of 
species is considerably less than in India and where, moreover, spawning 
does not go on the whole year round. In Europe each kind of fish has 
its Own spawning period whilst in India this is evidently not so or in a 
much lesser degree. These considerations make it appear doubtful whether 
we will ever succeed in determining all the different kinds of pelagic fish 
eggs occurring in the Indian seas, or even in such a restricted area as the 
Java Sea (between Borneo and Java), which is the field of investigation 
of the Batavian Laboratory for the Investigation of the Sea. But on the 
