BKEEDING-HABITS OF SOME WEST-AFEICAN PISHES. 



L29 



The eggs, which measure 2^ mm., then appear to hatch in about two days, though, 

 owing to the distance the nests were from my quarters, of this I am not certain. The 

 nest appears to be used for at most four or five days. As soon as the larvae are hatched, 

 they begin to strike up from the bottom. The day after hatching they may be seen 

 continually passing up and down, and are now provided with long external gill- 

 tilaments of a blood-red colour, but not so numerous or so long as in the case of 

 Gymnarclius (PI. XI. fig. 6 & 7). 



The following day they cease to pass up and down, and converging to a swarm about 

 one foot in diameter, form a deep continuous circle remarkable for its regularity and 



Text-fis. 21. 







Nesfc of Heterotis. 



persistence. The swarm occupies the exact centre of the little lagoon. The young fry, 

 which by now have lost the long external gill-filaments, are seen to be steadily 

 careering round and round ever in the same direction for at least a day. About the 

 fourth day the swarm becomes less persistent and regular, the larvae swimming first to 

 one side of the nest and then to the other, until about the fifth day they leave the nest 

 by the exit for a few trial trips attended by the parent, and finally leave it altogether, 

 swimming hither and thither in a dense swarm, from which the parent is never far 

 distant. I kept a large number of the young fry for several weeks, but could not get 

 them to feed, and eventually they all died. 



