HaSEMAX : ICxi'KDIllON T(1 CkNIRAL SoU III A M KK ICA. .S.33 



Nos. 2521-252,^ do nut lui\f two i-iitiri- rows of scales Ijctwoon 

 the lateral linr and the base of the first dorsal rays. 

 Xo. 2524, i2.,i cm., .Manaos, No\'. 15, i<)0<). 



1). X\', »); .\. Ill, S; 3.5-27-8; depth 2.33; head 2.H; eye 3.5; four 

 rows of scales on the cheeks; folds of the lower lips interrupted; six 

 gill-rakers on lower anterior arch; interorbital space 2.75 in head; 

 preorbital width eciiial to the diameter of the eye; dorsal and anal 

 fins scaleless; dorsal spines subeijual from the fourth, the last one of 

 which is not quite one-half the length of the head; the pectoral fin 

 as long as the head; snout a little longer than the postorbital por- 

 tion of the head; no distinct bands, bars, or spots, excepting a few 

 spots in the soft dorsal. There is a remarkable difference betw'een 

 specimens from different localities, but intermediate stages exist in 

 the same rivers. There are so many intermediate forms that it 

 appears to a collector that each genus consists of but one variable 

 species. This species was not found in the La Plata basin. 



14. A. centralis (Holmberg). Reported from Santiago de Estero. 

 Xo s[)eciniens were obtained by the Expedition of the Carnegie 



Museum. 



15. A. portalegrensis (Hensel). 

 ? Ilcros centralis Holmberg. 



Xo. 2545a— z", S-9 cm., Puerto Suarez, Bolivia, May 6-7, 1909. 



One specimen has twelve dorsal rays. 

 Xo. 25460-^, 3-8 cm., Arecpia, Paraguay, Lake Ipacary, April 8, 1909. 



Xo cross-bars; brown lines composed of spots along the row^s of 

 scales below' the lateral line. 



Xo. 2547, 9 cm., Sapucay, Paraguay. April 2, 1909. 

 Xo. 2548, 4.5 cm., Uruguayana, Rio LTUguay. Feb. 7, 1909. 

 Xo. 25490-6, 5 and 7 cm., Sapucay, Paraguay, April 5, 1909. 

 Xo. 2550, 9.6 cm., Corrego de Boa Ventura of Rio Barbados, June 16, 



1909. 



Depth 1.75; the maxillaries not quite extending to the eyes, 

 ^^'o. 993, 6 cm., Puerto Suarez, Bolivia. (Steinbach Coll.) 

 Xo. 25520-e, 1.7 to 7.3 cm., Cacequy, Rio Grande do Sul, Jan. 31 and 



Feb. I, 1909. 



The smaller specimens have only one row of scales on the soft dorsal, 

 and the depth is contained 2.16 times in the length. 

 Xo. 2553a-6. 1.5-3 cm. Villa Hays, Paraguay, .\pril 11-13. 1909. 

 Xo. 2554, 4.5 cm., Campos Alcgre, Rio Jauni, June 3, 1909. 



Depth is 1.84 of length. 



uj L I B R A R 



