PISCES. 89 



Sp. Malapterurus electricus Lac, Silu7'us eledricus Gmel., Encycl. meth., 

 Poiss. PI. 62, fig. 245, (copied from a figure of Broussonet ; see his me- 

 moir, Mem. de I'Acad. royale des Sc. de Paris, 1782, pp. 692 and following), 

 Cuv. R. Ani., ed. ill., Poiss. PI. 99 ; le trembleur; this fish lives in the 

 Nile and other rivers of Africa, in the Senegal, and even to the 19th deg. 

 south lat. in the Zambeze. Like the Torpedo and Gymnotus electricus it can 

 give shocks, concerning which Adanson, Forskal, and Broussonet have 

 imparted observations. The electric organ lies below the integument on 

 each side of the body, between two tendinous membranes formed of crossed 

 filaments, of which the innermost covers a layer of loose conjunctive tissue, 

 which has been regarded as a second or internal electric organ. The proper 

 electric organ is thickest at the abdomen, gelatinous, transparent, and con- 

 sists of many cells, visible to the naked eye, mostly rhomboidal ; it receives 

 its nerves from the nervus vagus. See Geoffrot Saint-Hilaire Ann. 

 du Mus. I. pp. 401 — 403, PI. 26, fig. 4; EuDOLPHi, Ahhandl. der Ahad. 

 der Wissensch. zu Berlin, aus d. Jahre 1824, s. 137 — 144, Taf. I. — iv. ; 

 J. MuELL. Handb. der Physiol, i. 3tte Aufl. 1838, s. 66 ; Valenciennes 

 Archives du Museum d'Hist. nat. 11. 1841, s. 43 — 61, PI. IV. ; W. Peter's 

 in MvEhiMR's Archiv, 1845, s. 375 — 377, Taf. 13, figs. 8— 11. This fish 

 is also eaten and noted for its flavour ; it attains a length of one to 

 two feet. 



Trichomycterus (Humboldt) nob. Body naked, round, com- 

 pressed towards the tail. Fins unarmed. Dorsal fin single, sup- 

 ported by rays. Teeth small, setaceous, crowded in jaws; palate 

 edentulous. Branchiostegous membrane with eight rays. Cirri 

 six, two filiform in front of nostrils, two conical maxillary at both 

 sides of mouth. 



Trwliomycterus Valenc. Ventral fiiis. 



Sp. Trychomycterus pimctulatus Valenc, Hist. nat. des Poiss. xviii. PI. 553, 

 &c. Fresh-water fishes from South America, which form the transition to 

 the genus Cohitis. They have, like the following genus, no swimming- 

 bladder. 



Eremophilus Humb., Valknc. No ventral fins. 



Sp. £renio2>hihts Mutisii ^VTABOhBT, Ohserv. de Zool. i. pp. 17 — 19, PI. vi., 

 Valenciennes, 1. 1. PI. 553, in fresh-water on the high table-land of 

 Bogota. Von Humboldt had already proposed for this fish the name 

 Trichomycterus, which Valenciennes has given to the species, discovered 

 at a later period, which have ventral fins. 



Family XIII. Cyprinoidei. Body almost always covered with 

 rounded scales. Dorsal fin single, radiate. Mouth small, edentulous, 

 in many cirrose. Branchiostegous membrane with three rays. In- 

 ferior pharyngeal bones armed with large teeth. Swimming- 



