328 FISHES OF WESTERN SOUTH AMERICA 
The Guianas and the Amazons 
15608, 2, the longer 561 mm., Iquitos, Allen, September, 1920. 
15809, 1, 405 mm. (tail broken), Iquitos, Allen, September, 1920. 
459. RHAMPHICHTHYS MARMORATUS Castelnau 
Rhamphichthys marmoratus Castelnau, 1855, Anim. Amér. Sud, Poiss., 86, pl. xlvi, fig. 2, Uruguay; 
EKigenmann and EKigenmann, 1891, Proc. U.S. Nat. Mus., XIV, 62; 
Kigenmann and Ward, 1905, Proc. Wash. Acad. Sci., VII, 168; 
Jigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, III, 449. 
Rhamphichthys pantherinus Castelnau, 1855, Anim. Amér. Sud, Poiss., 86, pl. xlvi, fig. 3, lake near 
Rio Ucayali; 
Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 5; 
Cope, 1878, Proc. Amer. Phil. Soc., XVII, 682, Peruvian Amazon, 
Steindachner, 1880, Denksch. IIx. Akad. Wiss. Wien, XLII, 38, Ucayali. 
Rhamphichthys lineatus Castelnau, 1855, Anim. Amér. Sud., Poiss., 87, pl. xlvii, fig. 1, tributary of 
Rio Ucayali; 
Kaup, 1856, Cat. Apod., 130, fig. 5. 
Gymnotus rostratus Steindachner, 1868, Sitzb. Kx. Akad. Wiss. Wien, LVIII, 8, in part. 
Rhamphichthys rostratus (in part) Ellis, 19183, Mem. Carnegie Mus., VI, 187. 
Rio Orinoco and the Guianas southward to La Plata 
15423, 1, broken, the piece 330 mm., Iquitos (?), Allen, 1920. 
Much resembles R. rostratus, the postorbital part of the head greater, however, 
2.4 in the length of the head, the eye bisecting the distance between the snout and 
pectoral basis. In size the specimen evidently lies between the extreme lengths of 
the three specimens of R. rostratus, in all of which the postorbital part of the head 
is one-third the total length of the head. The elongation of the snout places it 
here rather than with rostratus. 
Subfamily: GYMNOTINAE 
Genus 185: GYMNOTUS Linnaeus 
Gymnotus Linnaeus, 1758, Syst. Nat., ed. x, 246; 
Cuvier, 1817, Régne Anim., II, 235; 
Giinther, 1870, Cat. Fish. Brit. Mus., VIII, 10; 
Bigenmann and Ward, 1905, Proc. Wash. Acad. Sei., VII, 174; 
Eigenmann, 1910, Rept. Princeton Univ. Exped. Patagonia, HT, 450; 
Ellis (in Eigenmann), 1912, Mem. Carnegie Mus., V, 425; 
Ellis, 1913, Mem. Carnegie Mus., VI, 116 (contains a very comprehensive bibliography of 
the genus); 
Eigenmann, 1922, Mem. Carnegie Mus., LX, 171. 
Type: Gymnotus carapo Linnaeus 
Range that of the one species 
No frontal fontanel; anal basis not continuing as a false caudal fin around the 
end of the tail, which is terminal and cylindrical; body scaled, teeth conical, a single 
row in each jaw; not electric. 
