130 MEMOIRS OF THE CARNEGIE MUSEUM. 
Body and head compressed; width of the head 2.25 to 2.4, depth of the head, 
at base of the occipital process, 1.5 to 2 in the greatest depth; anus on or slightly 
behind the vertical from the posterior margin of the eye; dorsal profile regularly 
and moderately convex; ventral profile varying from rather weakly convex to 
markedly so. 
Snout heavy, short and blunt; mouth moderate; gape short to medium; jaws 
about equal, the lower included on the sides, teeth present in both jaws; eyes small 
to medium. Caudal peduncle 3.25 to 4.75 in the total length; origin of the anal 
below, or slightly behind, the origin of pectorals; pectorals about 1.2 in the head. 
Ground color of alcoholic specimens, buff; dorsal and dorso-lateral parts more 
or less overlaid with greenish brown, belly lighter; the lateral line and three stripes 
which parallel it dark (any or all of these stripes which are ventrad to the lateral 
line may vary considerably in width and intensity, may even be wanting); a black 
bar at the origin of each anal ray; fins hyaline; caudal peduncle blue-gray above 
and pale yellow below. 
In life Kigenmannia virescens is quite translucent, and is of a bright reddish 
color. The head and pectoral regions are orange to yellow and the caudal append- 
age greenish. This species is capable of changing color to some extent (See dis- 
cussion of color). 
The markings of the different individuals vary considerably according to the 
presence or absence of the dark blue stripes above the anal fin. Specimens from 
clear water usually show well developed stripes and have the head much darker 
than those found in muddy water, and may have the anal fin fringed with dusky. 
The chromatophores are more numerous over the entire body of those from clear 
water. 
This species is classed among the food-fishes, though it is not much sought 
after by the white people. The coolies of British Guiana seem particularly fond 
of this fish, which, with the other Sternopygine, they call the “ Loga-Loga.” In 
addition to the name ‘‘Cuchillo” or “Cuchilla”’ applied to it by most Spanish- 
speaking creoles, it is known as ‘‘Macana” and ‘Raton blanco” in the United 
States of Colombia and Venezuela, and “‘Tuviras” in Brazil. It is found abund- 
antly in the trenches and ditches on the plantations, where it feeds among the 
weeds. Its natural habitat is in the small streams which flow through savannah 
or open country in the lowlands. 
Because of its large range several varieties have been described as separate 
species, but these intergrade. ‘“‘ Humboldti” of Steindachner may be a distinct 
variety. It is found along the west coast and in the Rio Magdalena system. 
Specimens answering its description have been taken in Guiana and Brazil. 
Distribution: Rio Magdalena and west coast south over the whole of eastern 
South America to the Rio de la Plata. 
