308 Fretp Museum or Natura History — Zoétocy, Vo. X. 
“Head 7.25 (old individuals) to 11 (young individuals); depth 8.5 
to 14 in length to end of the anal; anal rays 200 to 260. 
“Snout 2.5 to 3; interorbital 2.25 to 3 in head; eye 4 (young) to 7 in 
the snout, 4.25 to 6 in the interorbital, ro to 6 in the head. 
“Body cylindrical; head depressed; width of head 1.25 to 1.6, depth 
of head at base of the occipital process 1.3 to 1.8 in the greatest depth; 
anus near the vertical from a point the length of the snout behind the 
eye; dorsal profile almost straight; ventral profile slightly convex. 
“Snout very slightly pointed in young specimens, blunt in adults; 
mouth rather large; gape straight, reaching about two-thirds of the 
distance to almost below the eye; upper jaw included; caudal peduncle 
one-half the length of the snout or less; pectorals 2.25 to 3 in the head; 
origin of the anal behind pectorals, on the vertical from a point about 
1.5 times the snout behind the head. 
“Ground-color of alcoholic specimens varies from a light slate-gray 
in young specimens to a light orange in adults; a series of transverse 
white stripes crossing the body in young individuals, which widen and 
become yellow with age so that the adults are yellow, barred with black; 
dorsal parts washed with a dark chocolate-brown containing numerous 
black spots; fins translucent, mottled with black or brown. 
“Tn life the body is translucent, flesh color or pale yellow, vary- 
ing to a distinct pink in the parts rich in blood. The stripes and 
markings are blue or green, giving the fish a purplish or olive-green 
cast. This color may be deepened or lightened slightly by the ex- 
pansion and contraction of chromatophores. 
“The general marking of the species varies considerably, specimens 
from clear water being darker and more striped than those from muddy 
water. Some specimens from Guatemala and from the Upper Paraguay 
are almost without markings.” (Ellis) 
This species was not taken in Panama, but it is here included because 
it has been recorded from Central and South America, thus coming 
within the range of the present work. 
Habitat: Guatemala south to the Rio de la Plata, and the West 
Indies. 
34, Genus Sternopygus Miiller & Troschel. 
Sternopygus Miller & Troschel, Hore Ichthyol., III, 1849, 13 (type 
Gymnotus macrurus Block & Schneider). 
Differing from all other Gymnotids in the free orbital margin. Body 
elongate, compressed; head moderate; snout short; jaws equal, or the 
upper a little in advance of the lower, the latter included at sides; teeth 
minute, in 2 more or less distinct patches in upper jaw, in a single patch 
