16 ON THE SPECIES OF THE GENUS ANOSTOMUS. 



itlarius will not permit its admission. Apparently it is the 

 young of Rhytiodon argenteo-fuscus. The fourth tooth on 

 each side in that species is very small and from its position 

 against the third is not readily discovered. The teeth of the 

 species of Rhytiodou differ considerably, and Kner's figures 

 of those of R. microlepis do not well represent those of 

 R. argenteo-fuscus, which latter agree somewhat well with 

 those of S. Sagittarius as described. Aside from the six 

 teeth on the mandible there is nothing in the description 

 that will separate Sagittarius and argenteo-fuscus. The 

 differences between Rhytiodus and Anostomus seem too 

 great to allow of bringing them together as subgenera. 



In the following table are indicated the different divis- 

 ions of the genus Anostomus with their contents. 



Snout elongate, narrow, sub-circular in cross section ; 

 mouth directed upward, lower teeth long, narrow, 

 crenulate' . . (ANOSTOMUS). 

 series of scales 4 from L.I. to D. ; 



flank with two longitudinal bands salmoneus. 

 series of scales 6 from L.I. to D. ; 



flank with two or more spots . trimaculatus. 

 Snout broad, sub-elliptic in cross section ; 



mouth directed obliquely upward and forward, 



lower jaw longer ; 

 lower teeth broad, truncate or chisel-shaped 



(SCHIZODONTOPSIS) . 



series of scales 5 from L.I. to D. ; 



a band along the flank . . . tceniatus. 

 series of scales 6 from L.I. to D. ; 

 a band along the flank ; 



transverse bands none . . proximus. 

 transverse bands four . . . varius. 

 series of scales 7 from L.I. to D. ; 



a band along the flank . . . orinocensis. 



