6 ON THE SPECIES OF THE GENUS CHALCINUS. 
Chalcinus ALBUS. 
Triportheus albus Cope, juv. 
Chalcinus Knerii St., adult. 
D. 11, A. 29-32, L.l. 30-33. 
Five scales between the first ray of the dorsal and the 
lateral line were present on all the specimens examined. 
The anal fin begins at a little distance behind the base of 
the dorsal. The middle rays of the caudal are not black 
as in the preceding ; the extremity of the fin is crossed by 
a black band, in front of which there is a white one. 
Secured at Manacapouru, Porto do Moz, Tabatinga, Ta- 
japura, Tefie, Rio Negro, Hyavary and Iga. 
Chalcinus elongatus Gth. 
"D. 11, A. 28, V. 8, L. 1. 45, L. tr. -f--" 
A considerable variation is to be seen in regard to the 
amount of convexity of the crown ; on the young or on 
the lean it is much less than on the more plump of the 
older ones. The barbels are more prominent on the young. 
The anal rays vary in number from 28 to 32, the scales in 
the lateral line from 43 to 48, and the scales between dor- 
sal and lateral line from 6 to 7. Next to C. angulatus, 
this species is probably the most common. It was taken 
at Arary, Cameta, Gurupa, Tga, Jose Fernandez, Jutahy, 
Lago Alexo, Lake Hyanuary, Lake Jose Assu, Manaca- 
pouru, Manaos, Montalegre, Obydos, Para, Porto do Moz, 
Rio Negro, Santarem, Silva, Lake Saraca, Tabatinga, 
Tetfe, Tonantins and Villa Bella. 
Chalcinus magdalen^e St. 
"D. 11, A. 35-41, V. 7, L. 1. 41." 
Six and a half to seven rows of scales above the lateral 
line, and one and a half rows below it to the ventral, or 
