POLYPTEEUS. 15 



The first observations on the habits of P. senegalus were made by the late 

 Mr. J. S. Budgett in the Gambia in 1899 * :— 



" In June and July sexually mature individuals were taken in numbers together ; 

 about three-fifths were females. The fish lies for long periods in the mud at the river 

 bottom with the fore part slightly raised and resting upon its pectoral fins like a seal 

 upon its paddles. If the water is a little stale it may be seen to move slowly forwards 

 by the action of its pectoral fins, which are worked very much as a lady uses her fan ; 

 the ventral fringing rays are deflected first, the more dorsally placed ones later, giving 

 the action, in which the whole shaft of the fin is involved, a screw-like appearance. 

 As it nears the surface, however, the whole of the body and tail is brought into action, 

 with a dart it strikes the surface, gulps in the air with its mouth, lets out the excess 

 by opening its spiracles, and with lightning rapidity returns to the bottom. 



" The only time Polypterus was seen to feed in the wild state, there was a small 

 shoal of P. senegalus making their way slowly along the river bank. One of their 

 number seized a fresh-water Crustacean, two others gave chase and, stirring up the 

 mud, they all disappeared. When seizing young fry or tadpoles, it proceeds stealthily 

 after them, propelling itself by the flutters of its fan-like fins until within striking 

 distance, and then with a sharp snap they are gulped down. 



" If the water is perfectly well aerated, Polypterus may lie for a long time without 

 breathing air ; but a specimen which had been perfectly happy in tolerably fresh water 

 for some days, when allowed to reach the surface, succumbed in a few hours when 

 prevented from so doing. On the other hand, one specimen lived for twenty-four hours 

 in a landing net, with no more water than the moisture of the atmosphere, and finally 

 had to be killed. 



"Polypterus may be watched for a considerable time, and give the impression that 

 it is a sluggish and inactive fish. If, however, one is lucky enough to observe a male 

 and a female sporting together, it will be seen that they are capable of wonderful 

 activity — executing the most lithe and supple movements, turning, twisting, darting, 

 and pausing in an extremely graceful manner." 



He concludes by stating that this species, as well as the larger P. lapradii, 

 " migrates to the flooded lands to spawn ; that without doubt it uses its air-bladder as 

 an accessory organ of respiration and seldom as an hydrostatic organ, as a rule being 

 unable to float, though it should be mentioned that, preparatory to sporting near 

 the surface, it was seen to take in several gulps of air in succession. The spiracle is 

 used for the emission of air and not for the passage of water. The pectoral fins are 

 important organs of propulsion and not mere balancers, as in almost all Teleo&tomes." 

 I have myself observed several living specimens from the White Nile, kindly 

 forwarded to me by Mr. Loat, which I have kept in an aquarium for more than 



* Proc. Cainbr. Philos. Soc. x. 1900, p. 236. 



