GYMNOTID^. 



distance behind the throat. Humeral arch attached 

 to the skull. llibs well developed. Gill-openings 

 rather narrow. Air-bladder present, double. Stomach 

 with a csecal sac and pyloric appendages. Ovaries 

 with oviducts. 



Freshwater fishes from Tropical America. 



Si/)i02ysis of the Genera. 



A. Body scaly; no electric organ. 

 I. Caudal fin present. 



A rudimentary dorsal fin 1. Steunarciius, p. 2. 



II. Tail terminating in a free point. 



Teeth none 2. EuAMrnicHTnYS, p. 4. 



Both jaws with a patch or band of very small teeth. 



3. STEa.NOPYGUS, p. 7. 



A series of conical teeth in each jaw ... 4. Carapus, p. 8. 



E. Body naked ; an electric organ. 



A series of conical teeth in each jaw ... 5. Gymnotus, p. 10. 



1. STERNARCHUS. 



Sternarchus, sp., Bl. Schn. p. 4'.>7. 



Apterouotus, Lacep. ii. p. 2U(S. 



Sternarchus, Ciw. Rlgne Anim. ; Mull. ^" Trosch. Hor. Ichflii/ol. in. 



p. 15 ; Reinhardt, Videmk. Meddel. naturh. Foren. Kjohenh. 1852 



(1853), or Wk'ijm. Arch. 18.54, p. 183. 



Tail terminating in a distinct small caudal fin. Teeth small. A 

 rudimentary dorsal tin is indicated hy an adipose band fitting into 

 a groove of tlie back of the tail ; it is easily detached so as to appear 

 as a thong-like appendage, fixed in front. Branchiostegals four. 



Brazil and (iuyanas. 



The species may be divided into two subgenera : — 



a. Stern auchus. Snout compressed, of moderate knc/fh. 



1. Sternarchus albifrons. 



Gymuotus albitVons, Z. Sij-d. Nut. i. p. 428; Pall. Spic. Zuol. vii. p, 36, 



tab. (3. fig. 1. 

 Apteronotus passan, Lacep. ii. p. 209, pi. 6. fig. 3 (bad). 

 Sternarchus albifrons, Bl. iSchn. p. 407, tab. 04 ; (jasteln. An. Amer. 



Hud, Poiss. p. 01, pi. 45. fig. 1 ; Kaup, Apod. p. 12(j ; Steindachner, 



Sitzijsh. Ak. Wiss. Wien, 1868, Iviii. p. 240. 



lacepedii, Casteln. I. c. p. 93, pi. 45. fig. 3. 



maximiliani, Casteln. I. c. p. 93, pi. 45. fig. 4. 



Snout compressed, of moderate length ; eye small, nearer to the 



