QYMNOTIDiE. 137 



Genus 3. STERNOPYGUS, MiiU. d Trosch. 



Diagn. Card-like teeth in many rows. 



Descr. Head and body compressed, head bhtnt, with small jaws. 

 Sometimes there are traces of card-like palatine teeth. Tlie 

 tapering tail becomes very slender, and is destitute of a caudal fin. 

 The largest scales lie along the lateral line. In its entire habit 

 this genus resembles Fierasfer. 



I J.. Sternopygus machourus. 



Sternopvgus macrourus, Miill. d Trosch. loo. cit. p. 14 ; Block, 157, 



2; Bl. d- Schn. 52-2. 

 Carapus macrourus, Cuv. Rhjn. An. ii. p. 357. 

 Carapus arenatus, Eyd. et Soul. Bonite, i. p. 24, pi. 8, f. 1. 

 Carapus sangainolentus, Castelneau, pi. 46, f. 1. 

 Sternopygus Marcgravi, Reinhardt, I. c. 180. 



Diagn. Eyes provided with lids. 



Descr. Easily known by its diagnosis, and by its carp-like head 

 and high, thick nape, which is depressed posteriorly. The diameter 

 of the eye varies, so that its employment as a measure of other dis- 

 tances must lead to error. The normal colour is yellowish-brown, 

 with numerous dark points. On the nape, above the gill-plate, 

 there are frequently large round spots with or without white dots. 



In a male specimen, labelled arenatus, there is a broader or nar- 

 rower longitudinal yellow stripe on the posterior half of the tail, 

 under the lateral line, which, in the males, is scarcely the twelfth 

 part of an inch broad, and in parts wholly disappears. 



A small individual in the Paris collection, which was presented 

 by Sir Robert Schomburgk, is blackish, with cross-bars and longi- 

 tudinal stripes near the brim of the back. Bloch figures his speci- 

 men with round spots scattered over the whole body. I have seen 

 many specimens, but not one like his. 



The e.xamples distinguished by the name of arenatus were col- 

 lected in the Guayaquil, a river of Equador. Schomburgk's were 

 probably fished in the Essequibo of British Guiana ; and those 

 which Reinhardt has described came from the Rio das Yelhas, one 

 of the tributaries of the Brazilian San Francisco. It may therefore 

 be considered as probable that the species is a general inhabitant of 

 the rivers of South America. P. 10; A. 230-274, and 310 rays 

 according to Johannes Miiller, It attains a length of two feet or 

 more. 



T5. Sternopygus virescens. 



Sternarchus virescens, Valenc. in D'Orhig. Voy. pi. 132. 

 Sternojiygus tumifrons, Midi, d Trosch. I. c. 14. 

 Sternopygus microstomas, Reinhardt, I. c. 181. 



