460 PARENTAL CARE AMONG FRESH-WATER FISHES. 



tiiil and returninjj: tbrougli the surroundings; it stuns small fish in the neigh- 

 borhood and can l)e felt by man, when the hand is placed near the fish, as a 

 smart shock reaching up the arms to the shoulders. 



The seeker for further information may find it in the article on 

 " The electric fish of the Nile," by Professor Gotch, in the Proceed- 

 ings of the Royal Institution of Great Britain for March 17, 1891) 

 (voL 16, pp. 114-115). 



The raad has a wide range through Africa and occurs not only in 

 the Nile, but in the other great rivers, the Kongo and the Niger, 

 besides many smaller intervening streams. 



In a state of nature the raad attains a considerable length, excep- 

 tionally as much as 3 feet, but is mature and capable of reproduction 

 when less than a foot long. According to Forbes, individuals in con- 

 fined quarters or captivity scarcely ever grow ; " most " of those in 

 the Liverpool Museum — about 6 or 7 inches long — have r.arely, 

 though in excellent health, grown nnich after their arrival." The 

 largest the present Avriter saw in an aquarium in Liverpool was less 

 than 8 inches long. In the aquaria of the Egyptian Zoological 

 Gardens, however, the director reported (1905, p. 27) that specimens 

 " increased in length and girth during their stay in captivity." One 

 which died in February, 1905, had attained a length of 174^ inches 

 and a weight of over 3 pounds (3.2 pounds), after having lived nearly 

 two 3'ears (since April, 1903) in the aquarium. 



A number of good observations were made on individuals living in 

 the Liverpool Museum, by Dr. H. O. Forbes, and i)ublished in the 

 Bulletin (I, pp. 25, 20). These we freely draw upon. For the most 

 time and " when in good health the raad lies sluggishly on the bot- 

 tom, rising to the surface only for the purpose of feeding or when in 

 expectation of being fed." Those in the Egy^Dtian aquarium '* ap- 

 pear to spend nearly the whole day lying motionless on the bottom 

 of the tank, from time to time flapping their pectoral fins." In cap- 

 tivity in Liverpool they " thrive well on and take with avidity com- 

 mon earthworms, boiled liver chopped up, and occasionally a young 

 trout from two to three inches in length." Its power of vision is very 

 limited, although it has " small, sparkling, diamond-point-like eyes," 

 but their optic nerves are " extremely attenuated," when compared 

 Avith those of "" other fishes of corresponding size." Its behavior in 

 being fed is characteristic. 



If a worm be dropped into the tank to fall wriggling to the bottom, the Ma- 

 lapteriirus rarely, if ever, sees it. A few moments, however, after the worm 

 has fallen through the water, the fislr becomes suddenly agitated, apparently 

 through its olfactory organ, or, perhaps, by its barbels detecting the undula- 

 tions comnumicated to the water; and begins turning ra])idly about with tensely 

 extended and vibrating barbels, keenly quai-tering out the tank in quest of the 

 quari-y. whose presence it has become sensible of. The sought-for object is, 

 however, as a rule, discovered without its coming into actual contact with the 



