THE GYMNOTID EELS OF TROPICAL AMERICA. 155 
XV. SrernarcHociron Higenmann and Ward. 
Sternarchogiton EIGENMANN AND Warp, Proc. Wash. Acad. Sci., VI, 164, 1905. 
Type, Sternarchus nattereri Steindachner. 
Distinguished by the absence of teeth in the upper jaw, otherwise like Stern- 
archus. 
A genus of a single species. 
Fia. 16. Sternarchogiton natterert (Steindachner). 
26. Sternarchogiton nattereri (Steindachner). 
Sternarchus nattereri STEINDACHNER, Die Gymnotida, 3, pl. H, fig. 1, 1888 (Barra 
do Rio Negro); Ginruer, Cat., VITT, 3, 1870; EIGENMANN AND EIGENMANN, 
Proc. U. §. Nat. Mus., XIV, 1891, 62; BouLencEr, Trans. Zodl. Soc., XIV, 
427, 1898 (Rio Jurua). 
Sternarchogiton nattereri EIGENMANN AND WarD, Proc. Wash. Acad. Sci., VII, 165, 
1905 (Barra do Rio Negro; Jurua); VON [WERING, Os Peixes do Brazil, Part 
1 A, 1907; Ercenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 
448 (Barra do Rio Negro). 
“Teneth of the head about 12, depth of the body a little more than 8 in the 
total length; snout 3.5, pectoral 1, the caudal about 2 in the length of the head; 
anal rays 197; the pointed pectoral with 16 rays; the almost completely scaled 
caudal with 18 or 19 rays. Scales of the lateral line and the neighboring ones 
larger than the others. 
“Upper jaw without teeth, those of the lower small and in a single row.” 
(After Steindachner. ) 
Distribution: Middle and Upper Amazons. 
XVI. ADONTOSTERNARCHUS genus Nov. 
Type, Sternarchus sachsi Peters. 
Distinguished from all other Sternarchine by the absence of teeth from both 
jaws, and by the peculiar V-shaped groove in lower jaw into which the beaklike 
upper fits. 
A genus of a single species, A. sachsi. 
