40 
Indiana University Studies 
very slightly emarginate, the longest ray 2 times in the head ; 
anal sheath consisting of only 2 to 4 scales, covering the first 
4 to 8 rays ; caudal lobes equal to the head in length. 
Humeral spot distinct, vertical, separated from the head by 
1 or 2 scales ; a dark silvery lateral band half the total length 
ending in a small black caudal spot that is not continued on 
the middle caudal rays; numerous chromatophores on the 
head and body, thickest on the back and above the anal, very 
few on the abdomen below the lateral line ; fins unmarked. 
Astyanax abramis ( Jenyns) . 
17166, 1, 118, mm., Lower Bopi. Sept., 1921. 
17167, 2, 78 and 90 mm., Rio Colorado, Lower Bopi. Sept., 1921. 
17168, 5, 86-122 mm., Popoi River, Upper Beni. Sept., 1921. 
17169, 13, 95-142 mm., Ixiamas. Dec., 1921. 
17170, 15, 76-128 mm., Huachi. Aug., 1921. 
17171, 54, 58-120 mm., Rurrenabaque. Oct., 1921. 
17304, 5, 34-75 mm., Rio Iniqui, Upper Beni. Sept., 1921. 
These specimens like the types have the chromatophores 
collected along the bases of the scales to form rows of spots. 
Astyanax bimaculatus (Linne). 
17163, 1, 90 mm., Lake Rogoagua. Nov., 1921. 
17164, 1, 108 mm., Reyes. Nov., 1921. 
17165, 44, 42-78 mm., Huachi. Aug., 1921. 
17178, 185, 12-80 mm., Cachuela Esperanza. Mar., 1922. 
17179, 22, 18-30 mm., Lagoons, Lake Rogoagua. Nov., 1921. 
17228, 2, 28-35 mm., Rurrenabaque. Oct., 1921. 
Several of the above specimens have rows of spots in the 
middle of the scales and thus agree with A. bimaculatus Para - 
guay ensis. 
Astyanax lineatus (Perugia). 
17172, 21, 65-122 mm., Rio Colorado, Lower Bopi. Sept., 1921. 
17173, 50, 55-98 mm., Popoi River, Upper Beni. Sept., 1921. 
17174, 48, 45-158 mm., Huachi. Aug., 1921. 
17175, 63, 48-88 mm., Rurrenabaque. Oct., 1921. 
17176, 16, 68-112 mm., Ixiamas. Dec., 1921. 
17177, 18, 55-128 mm., Tumupasa. Dec., 1921. 
17303, 3, 55-65 mm., Rio Iniqui, Upper Beni. Sept., 1921. 
The above specimens have the dark lateral bands formed by 
the collection of chromatophores along the lateral edges of the 
scales. This distinguishes them from Eigenmann’s new 
