20 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



der spot differs very widely in distinctness. A similar condition exists 

 at the northern end of the range of this widely distributed species. 

 Specimens from Nicaragua {(crstedH) are not distinguishable. A bet- 

 ter marked variety is the many-toothed nlcdraguensia. Still further 

 north comes xneas^ and tiuall}' inexicanus. It will take a large series 

 of specimens to demonstrate the validity of these varieties. 



I add details of a numljer of specimens in the museum of Indiana 

 University and the National Museum. 



Specimens collected by elohn W. Titcomb for the U. S. Fish Com- 

 mission at Cordova, Argentine, are like those collected b}" Page in 

 Asuncion, Paraguay. 



a 88 mm. to base of caudal. Depth 2f; A. 27; ej^e 3 in head; 

 maxillar}^ ver}- slightly longer than eye; bony interorbital 8 in head; 

 shoulder spot not evident. 



h 94 mm. to base of caudal. Depth 2.8; A. 30; eye 3.2 in head; 

 maxillary equal to eye; bony interorbital 2.9 in head; shoulder spot 

 faint. 



c 101 mm. to base of caudal. Depth 2.75; A. 28; eye 3 in head; 

 maxillary equal to ej^e; bon}^ interorbital 3.2 in head; shoulder spot 

 faint. 



No. 9267. Museum of Indiana University. Rio Tiete, Brazil, Von 

 Ihering collection. 



a 90 mm. to base of caudal. Depth 2f ; A. 27; eye 3; maxillary 

 slightl}^ shorter than eye; snout 3.7; interorbital equal to eye; scales 

 6-36-6. A very faint humeral spot. 



h and c are much deeper. 



I 97 mm. to base of caudal. Depth 2.25; A. 26; eye 3.1; maxil- 

 lary equal to eye; snout 4 in head; interorbital 2.8; humeral spot 

 scarcely evident; scales 6-34-5. 



c 99 mm. to base of caudal. Depth 2.25; A. 24; ej'e 3.3; maxil- 

 lary equal to ej^^e; snout 4 in head; interorbital 2.8; humeral spot 

 scarcely evident; scales 6-34-(). 



These specimens are all nuich deeper than the usual rutiJus. 



No. 10788. Museum of Indiana University. Rio Tiete, Brazil, Von 

 Ihering collection. 



a 63 mm. to base of caudal, 78 mm. to tips of caudal. Depth 2.5; 

 A. 23; eye 3; maxillary' slightl}^ shorter than ej^e; snout 4; interor- 

 bital equal to eye; scales 5-35-5. A vertical humeral spot; caudal 

 band almost obsolete. 



h 48 mm. to base o,f caudal. Depth 2.66; A. 25; scales 5-35-5. 



These specimens are much slenderer than the older ones from the 

 same place. Caudal band reduced to the minimum; shoulder spot 

 well developed. 



No. 10786. Museum of Indiana University. Rio Grande, a tribu- 

 tary of the Parana. 



