686 ANNA LOWREY 
DESCRIPTION OF THE FISH 
Steatogenys elegans (Steindachner) was described in 1880 from 
specimens collected in the Barra de Rio Negro, Brazil. More 
recently it has been taken in the Rio Jurua, Brazil;! in the De- 
marara river, British Guiana;? and in the Amazon at Manaos, 
Brazil.’ 
Like other members of the family of Gymnotidae this fish is 
found only in fresh waters. It is a small flesh-colored, eel-shaped 
fish marked with six or more large purplish, wedge-shaped 
blotches, and distinguished from other gymnotids by two peculiar 
submental filaments. An average individual is about 125 mm. in 
length, and 13 mm. in the region of greatest depth. The head is 
small and chubby, and the small eyes are placed nearer the tip of 
the snout than the gill-openings. Like all gymnotids of the sub- 
family Sternopyginae, Steatogenys elegans possesses but pectoral 
and anal fins. The caudal region terminates in a long, rat-like 
tail composed of elongated, cylindrical vertebrae. In the sub- 
mental region there are two fleshy filaments. 
THE SUBMENTAL FILAMENTS 
These fleshy filaments were discovered by Steindachner who 
figures them in his original description, and calls them fatty fila- 
ments, but offers no explanation of their function, but it has been 
suggested! that these peculiar structures were probably electric 
organs. | 
Each filament is about 9 mm. long and 5 mm. broad and termi- 
nates in a minute, median cup-shaped depression, located two or 
three mm. posterior to the anterior margin of the lower jaw. 
Posterior to this depression the filaments diverge, curving outward 
and upward to a point just in front of the base of the pectoral fin. 
Here the filament is anchored and receives a large nerve and blood 
vessel. Each filament, completely covered by the dermis, les 
within a groove. 
1Boulenger, Trans. Zool. Soc., vol. 14, p. 428, 1898. 
*Kigenmann, Fresh water fishes of British Guiana, Mem. Carn. Mus., vol. 5, 
p. 422 et seq., 1912. 
‘Ellis, The gymnotid eels, Mem. Carn. Mus., in press. 
*Hllis, |. c. 
