324 FISHES OF WESTERN SOUTH AMERICA 
452. PoROTERGUS TERMINALIS Eigenmann and Allen, sp. nov. 
15994, 1, 240 mm., type, Iquitos, Morris, 1922. 
15720, 2, 225 and 299 mm., paratypes, Iquitos, Allen, September, 1920. 
Similar in form to the type species P. gymnotus, and in many characters not 
unlike P. gimbel/; differs from the short-snouted gimbeli in the terminal position of 
the mouth, much longer head and greater depth; more resembles gimbeli in the 
number of anal rays, having many more than gymnotus; teeth much stronger than 
in either. 
Head 5.5-5.8; depth 5.33-5.66; A. 179-184; lateral line about 70; origin of 
anal under emarginate part of the opercle; anus a little behind the vertical from the 
eye; profile straight, eye placed high; depth of head equals its length less the opercle; 
interorbital width 4.5-5.5 in the length of the head to the end of the opercular 
spine; snout 3.2-3.3; mouth small, terminal; maxillary nearly vertical; teeth strong; 
in two series in each jaw; gill-opening not equal to the snout; scales on the sides, 
from the lateral line to the anal muscles, large, and from the lateral line upward 
much smaller, circular toward the naked back; naked part of the back extending 
down to the lateral line in front, much more narrowly restricted farther back; the 
pectoral fin equal to the length of the head less the opercle; back dusky, other parts 
colorless. 
Named for the distal position of the mouth. 
Genus 181: STERNARCHOGITON Eigenmann and Ward 
Sternarchogiton Eigenmann and Ward, 1905, Proc. Wash. Acad. Sci., VII, 164; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 448; 
Ellis, 1913, Mem. Carnegie Mus., VI, 155. 
Type: Sternarchus natterert Steindachner 
Middle Amazon to Peru 
Sometimes a few teeth appear in a single series in the lower Jaw, sometimes 
on the sides only, sometimes none; no teeth on the upper jaw; the head much 
compressed, the lower jaw grooved into the upper; back naked; scales above the 
lateral line much higher than long. 
KEY TO THE SPECIES OF THE GENUS STERNARCHOGITON 
a. Head smaller, about 12 in the length, eve larger, snout smaller, about 3.5... .. .....-natterert 
aa. Head larger, about 9, eve 7 in snout.......... Me reg iy sere Aap hse ta ees lt _...porcinum 
453. STERNARCHOGITON NATTERERI (Steindachner) 
Sternarchus natlerert Steindachner, 1868, Sitzb. Kk. Akad. Wiss. Wien, LVIII, 3, pl. u, fig. 1, Barro 
do Rio Negro; 
Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 3; 
Eigenmann and Higenmann, 1891, Proc. U. 8. Nat. Mus., XIV, 62. 
Sternarchogiton natlerer? Eigenmann and Ward, 1905, Proc. Wash. Acad. Sci., VII, 165; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 448; 
Ellis, 1913, Mem. Carnegie Mus., VI, 155. 
