394 SILUKID.E. 



15. MALOPTERURUS. 



Lacepede, Hist. Poiss. v. p. 90 (1803) *; Giinther, Cat. Fish. v. p. 219 (1864) ; 

 Boulenger, Poiss. Bass. Congo, p. 33(3 (1901). 



Body moderately elongate, cylindrical or a little depressed. No rayed dorsal fin ; 

 an adipose dorsal fin. Anal fin short. Pectoral fin without spinous ray. Ventral fin 

 with 6 rays. Three pairs of barbels : maxillary and two mandibular. Eye lateral, 

 without free border. Each jaw with a band of villiform teeth ; palate toothless. Gill- 

 opening short, restricted to the side. Air-bladder very large, free, extending to the 

 origin of the caudal region, divided into two by a constriction. An electric organ 

 extending over the whole body, from the head to the origin of the adipose and 

 anal fins. 



A single species, inhabiting the greater part of Tropical Africa and the Nile. 



The skull is entirely concealed under the thick skin ; it is much flattened and 

 remarkable for the extreme narrowness, in front, of the frontal bone, which is single. 

 The branchiostegal rays number 8. Vertebrae 41 to 44 (20-22 + 21-22). The neural 

 spines are low on the preecaudal region. Hyrtl has discovered a rudimentary inter- 

 spinous bone resting on the first neural spine. The pectoral area is not so firmly 

 attached to the skull as in other Silurids. 



The electric organ differs essentially from that of other fishes provided with such 

 batteries, being part of the integumentary system instead of being derived from the 

 muscles. It consists of rhomboidal cells of a fine gelatinous substance immediately 

 under the skin, which is villose, like velvet or felt. It is controlled by a single 

 ganglionic cell at the anterior extremity of the spinal cord. Contrary to what takes 

 place in other electric fishes, the current proceeds from the head to the tail. 



So numerous have the accounts been of the physiological experiments upon this 

 wonderful fish that I must content myself with referring the reader to the very full 

 bibliographical index in Ballowitz's recent work mentioned in the synonymy f. 



* Spelt Malapterurus. But this orthography should be rectified, since the name is formed of /ja\6s, 

 soft ; irrepov, fin ; and olpa, tail : therefore we can write Maloptemrus or Ilalacopterurus, but not 

 Malapterurus. 



t See also references in Boulenger, Poiss. Bass. Congo, p. 340. 



