fiYMNOTinyT;. 



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/iu)2^sis of the Genera. 



A. Bod)' scaly; no electric organ. 

 I. Caudal fm present. 



A rudimnntnrj dorsal fin 1. Steknarciius, p. 2. 



II. Tail terminating in a free point. 



Tectli none 2. RnAMiTiu htiivs, p. 4. 



Both Ja\v3 with a patch or band of vei-y small teeth. 



3. STE.INOrYfiUS, ]). 7. 



A series of eonical teeth in each jaw ... 4. Carai-us, p. 8. 



H. Bodj- naked ; an electric organ. 



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



1. STERNARCHUS. 



Steriiarclius, sp., IjL tScJui. p. 4i)7. 



Apteronotu.s, Lacrp. ii. p. 2J(S. 



Steriiarchus, Cuv. lii'i/uc Aiiiin. ; Miill. ^- I'rorich. Jlor. Icldlnjol. iii. 



p. 1-J ; Itcinliardt, ViJciisk. Meddcl. nidurh. Foren. Kjiihenli. 1852 



(185:3), m- Wicijm. Arch. 1854, p. 183. 



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

 rudimentary dor.sal fin is indicated by an adi})Oso band fitting into 

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

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



Brazil and tniyanas. 



The species may be divided into two subgenera : — 



a. STKRNARC'nus. >SnoHt compr<-fised, of moderate loiyfh. 



1. Sternarchus albifrons. 



Cxymnotus albifrons, Z. !Sijst. Nut. i. p. 428; Pcdl. Spic. Zool. vii. p. .30, 



tab. (3. fig. 1. 

 Apterouolus pas.san, Laccp. ii. p. 201>, pi. 0. fig. •] (bad). 

 .Sternarchus albifrons, IJ/. b'chn. p. 4!)7, tab. !)4 ; Castebi. An. Anier. 



>Si/d, I'oias. p. !)1, pi. 45. fig. 1 ; Kaup, Apod. p. 12(3 ; SteindacJuiery 



ISUzijsh. Ah. IFin.i. Jf7e«, 18(38, Iviii. p. 24'J. 



Incepedii, Cdsfc/n. I. r. p. 9.">. pi. 45. lig. 3. 



nia.Yimiliaiii, C'ciMeln. I.e. p. i).'3, pi. 45. iig. 4. 



8nout compressed, of moderate length ; eye small, nearer to the 



