BEEEDING-HABITS OF SOME WEST-APEICAN FISHES. 117 



had been torn to pieces by crocodiles and the fishes had escaped. I then rigged up 

 some temporary cages in pools by the river-side, into which I turned six pairs of 

 P. lapradei and fifteen pairs of P. senegalus. By the 30th of July there was sufficient 

 water in my swamp-enclosures to turn in the fishes, and there they seemed quite happy, 

 as the grass was now two feet high and I fed them regularly every night. The 

 enclosures were each eighteen feet lon<r and six feet wide. As soon as I put the food into 

 the water at one end of the enclosure the P. senegall came hurrying through the grass 

 from all parts, and greedily devoured it without the least appearance of shyness. 

 The P. lapradei, however, were considerably more shy, and continually damaged them- 

 selves against the wire netting. Thus the Polypteri remained until the 5th of 

 September, and though I examined every inch of the enclosure every other day, I 

 found no traces of eggs. 



The third method was not tried so frequently as I could have wished, as I could 

 not obtain anything like the number of Polypteri that I procured in the previous 

 season. The natives at this time use a kind of basket for catching fishes, which is called 

 the " wusungu." This they deftly drop over the fishes as they see them move in the 

 grasses, and putting their hand into the basket from above, draw forth the captives. 

 Whereas by this method I obtained an abundant supply of Polypterus last year at 

 the price of sixpence apiece, this year I raised the price to two shillings apiece and 

 was yet unable to get any large number of specimens. 



The first spawning female was brought to me on the 3rd of July. It was a Polypterus 

 senegalus, and, on holding it up by the head, it extruded successively twelve eggs. I 

 had two males with which I tried to fertilize these eggs. One by one I tried them : first 

 by placing them on the anal fin and on the vent of the male, then by mixing them with 

 the fluid obtained from the seminal duct, and lastly by mixing them with fluid 

 obtained from the minced testis. These eggs were then transferred to muslin stretched 

 on a frame and placed in a large quantity of river-water. They soon attached themselves 

 to the muslin, but though I watched them until late into the night, no further change 

 took place and they one by one decomposed. On cutting open the female I found to 

 my disappointment that there were no free eggs in the body-cavity, but that they were 

 all attached to the ovary by their follicles. 



. The next spawning female was obtained on July 19th, when a flsherman brought me 

 a female Polypterus lapradei which had two eggs in the oviduct and practically none 

 in the ovary. There were no free eggs in the body-cavity. 



On August the 9th a female P. lapradei was brought which had evidently spawned 

 some time ago. 



On August the 14th a female was brought which had nearly flnished spawning. 

 There were, however, no free eggs in the body-cavity. I tried to force out the eggs 

 from the ovary, and in this manner several came away fairly easily, and I made every 

 effort to fertilize them, but again without success. 



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