PARENTAL CAEE AMONG FRESH-WATER FISHES. 



427 



the thick vegetation of the flooded grass-lands. The eggs are minute, 

 and therefore the chances of finding them in a state of nature are 

 small in the extreme."' 



In 1902 Budgett went to Uganda and returned by way of the Nile, 

 in search of Poh-pterus. BeloAv Murchison Falls, during August, 

 he found Polypterus spawning and the fertilization of over a hundred 

 ova was secured, but this, '' the most promising attempt yet made 

 to breed Polypterus artificially, again failed." 



The youngest Polypterus yet found was an inch and a quarter 

 long. It had external gills as " long as the head. It was a most 

 beautiful object," above striped with black on a golden ground and 

 with a golden stripe running from the snout onto the end of the 

 stem of the external gill. It was " extraordinarily active, and, during 

 the moments when it was at rest, supported the weight of its body 

 on its pectoral fins, the blade of the fin being turned forwards and 

 Eot backwards as is usually the case in the adult." 



■^^ 



Fig. 18. — Polypterus Hcneyulus larva, 14 in. long, in a very cliaracteristie atlitiulo. After 



Budgett. 



At last, during a third voyage to Africa, in southern Nigeria in 

 the months of August and September, 11)03, Budgett succeeded in 

 obtaining eggs and milt of Polypterus senegalus in proper con- 

 dition and time. He was " able to fertilize a large quantity of eggs." 

 The earl}" development was found to be very similar to that of a 

 batrachian — " astoundingly frog-like " was his first announcement — 

 '' the segmentation being complete and fairly equal and the process 

 of invagination resembling that of the frog's egg. I*rominent ven- 

 tral folds are formed which arch over in the normal fashion." 



A characteristic of the Polypterids is the develoi)meut and reten- 

 tion for a long time of the peculiar external larval branchia: or gills, 

 one on each side, reminding one of similar structures in the Dipnoans. 

 These have a featherlike form, with a tapering cutaneous axis 

 bordered by rows of barblike fi.laments above and below, converging 

 into a terminal portion; they originate behind the upper extensions 

 of the branchial apertures. Their persistence is variable, and some- 

 times one may last much longer than the other, as in a specimen of 

 the Polypterus eongicus, nearly 9 inches (22 cm.) long, Avhich 

 retained the right gill but had lost the left one. 



