XXI OSTARIOPHYSI 591 
in numerous bands, baskets of the small Fish being filled by 
the Indians who come across them.' The African Synodontis 
are much in the habit of floating or swimming leisurely on the 
surface with the belly in the air, as was well known to the 
ancient Egyptians, who have frequently depicted the Fish in 
this anomalous position. A curious fact in connexion with 
this habit is that S. membranaceus and S. batensoda, in which 
it has most frequently been observed, show an inversion of the 
ordinary mode of coloration, the lower parts being dark brown 
Fre. 357.—Synodontis decorus, from the Congo. 3 nat. size. 
or black and the upper pale silvery grey. The electric Cat-Fish 
(Malopterurus electricus), is also a native of Africa, occurring all 
over the tropical parts of that continent and also in the Lower 
Nile, growing to a length of three feet. Its flesh is more 
esteemed than that of other Silurids. It avoids light and is slow 
in its movements. The electrical apparatus differs absolutely 
from that of all other Fishes, being derived from the integument, 
belonging to the glandular system, and surrounding the whole 
body with a thick coat of grease or gelatinous substance; the 
apparatus is governed by a single nerve on each side proceeding 
from a huge ganglionic cell at the anterior extremity of the spinal 
cord.” The shocks given by Malopterurus are very powerful, and 
the Fish is called “ Raad” by the Arabs, a name which means 
“thunder.” Kept in an aquarium with other Fishes, even of the 
same species, the “ Raad” soon kills its companions. 
1 Cf, Hancock, Zool. Journ. iv. 1829, p. 242. 
2 Cf. G. Fritsch, ‘‘ Die Elektrischen Fische, I. Malopterwrus” (Leipzig, 1887) ; E. 
Ballowitz, ‘‘ Das elektrische Organ des Afrikanischen Zitterwelses” (Jena, 1899). 
