410 A Revision of the 



tognathi have demonstrated a similar state of affairs among that 

 group. 



The key to the species of the genus Ourimatus may prove to be 

 erroneous or insufficient in parts. If so, it is due to the fact that 

 we could not have the specimens before us when revising the 

 key. One species of Ourimatus, C. alherti, has been omitted, as 

 we had no description of it. Dr. Giinther, in his paper on the 

 fishes of the Rio Plata, states that it is related to Curimatus 

 platamis, but with considerably larger scales. 



In order to shorten the references in the synonymy, the titles 

 of works are not quoted, but each paper is referred to as '* a/' 

 ^''b," etc., after the year of its publication. " Steind., '75c" 

 refers to Dr. Steindachner's paper, '' Die Siisswasserfische des 

 siidostlichen Brasiliens," as will be seen by referring to the Bib- 

 liography given at the end of our paper. When but one paper 

 was published in the year by an author, it is referred to by the 

 year of its publication, as: "Gthr., ^64" refers to vol. v. of 

 Dr. Giinther's Oatalogue of the Fishes of the British Museum. 



The genera of the edentulous Oarimatinae may be distin- 

 guished by the following key: 



a. Gill-arches with loBg, slender rakers. Anodus. 



aa. Gill-arches without rakers. 



h. Postventral region trenchant, the scales of each side with a nar- 

 row margin bent over the ventral ridge and terminating 

 medially in a spiniform process, 

 c. Scales in lat. 1. 94-103. Preventral region flat, with blunt lateral 

 keels. Median line in front of dorsal naked. A. 16-17. 



POTAMORHINA. 



cc. Scales in lat. 1. 50-60. Preventral region rounded. Predorsal 



region entirely scaled. A. 10-12. Psectrogaster. 



hb, Postventral region trenchant or not, always with a median series 



of scales which do not terminate in spiniform processes. 



d. Lateral line developed on anterior scales only; mouth oblique, 



the lower jaw entering the profile. Tongue long and narrow, 



quite free. Curimatopsis. 



dd. Lateral line complete. Mouth horizontal or slightly oblique. 



Tongue short and thick, adnate. Curimatus. 



J. AlVODUS. 



Anodus Spix, '29a, 60 {elongatus and latior); M. and T., '45a, 6 (sp.)^ 



Cope, '78a, 682 (elongatus). 

 Elopomorphus Gill, '78a, May 21st[{jordani). 



