416 A Revision of the 



h. Depth 2^-3. elegans bahiensis, lOa^ 



k-i. No dark line on sides. 



m. Scales 37. argenteus, 11. 



ms. Scales 8-44 to 47-5; dorsal and caudal spots distinct. 



Mmaculatus, 12. 

 7)13. Scales 8-48 to 52-6; dorsal and caudal spots indistinct or 

 wanting. A brown bar at base of caudal. 



Mmaculatus sialis, 12a. 

 Ca. Middle caudal rays plain. ^ 



n. A black spot at base of dorsal. 

 0. Lateral line 48 to 52. bimaculatus trachystethus, 12b. 



02. Lateral line 43. dobula, 18. 



Os. Lateral line 34. guntheri, 14, 



012. Dorsal plain. 



p. Back uniform in color. 



q. Less than 60 scales in the lateral line. 

 r. Lateral J. 32-34. microcephaXus, 15. 



r.2. Lateral 1. 36-41. ^ 

 s. Ventrals not reaching to the vent. 

 t. Preventral region without a median series of en- 

 larged scales. gilberti, 17. 

 ^2. Preventral region with a median series of en- 

 larged scales. gilberti brevipinnis, 17a. 

 Sa. Ventrals reaching to vent. plumbeus, 18. 

 Vz. Lateral 1, 44-47. 



u. D. 10; scales 8-44-7. ndgelii, 19. 



«2. D. 12-13; scales 7-45 to 47-6. leucostictus, 20. 

 Vi. Lateral 1. 49 to 55. 

 V. Depth 2^-3. 

 IV. Scales entire. platanus, 21. 



w-i. Scales serrated. 

 X. Scales 13 or 14-51-9; mouth subinferior. 



asper, 22. 

 x^. Scales 11 or 12-50 to 53-8. 



rutiloides, 23. 

 v^. Depth 4. hypostomus, 24. 



ga. Lateral line with 60 or more scales. 



y. Scales 16 or 17-69 or 70-12 or 13. 



mivartii, 25. 



y.2. Scales 10-60 to 69-8. leuciscus, 26. 



Pi. Back with dark cross-bars. vittatus, 27. 



^ In order to bring this index within the proper limits of the page- width, 

 the position of Ca has been transferred at this point to the left-hand edge. 

 * 16, C. magdalence should be placed here. 



