THE AMERICAN TETRAGONOPTERINAE. 223 



Head 3.2 to 3.7; depth 2.6 to 2.8; D. 11; A. 16 to 18; scales 6-33 to'36-5; 

 eye rather small, 3 in the head; interorbital equal to or greater than the eye, 

 2.8 to 3 in the head. 



Compressed. Depth of head at the base of the occipital process 1.6 in the 

 greatest depth. Predorsal region rounded, with or without a complete series 

 of 11 median scales. 



Occipital process short, about 6 in the distance from its base to the dorsal, 

 bordered by 2 or 3 scales. Frontal fontanel an almost equilateral triangle, 

 narrower than the parietal fontanel and 1.6 in the parietal without the occipital 

 groove. Second suborbital leaving a naked margin behind and below. Snout 

 short and moderately blunt, less than the eye, 4 in the head. Maxillary shorter 

 than the eye, equal to the length of the snout, elliptical in outline, the front and 

 back not parallel. Mandible equal to the eye. Premaxillary with four or five 

 5- to 7-pointed teeth in the inner row, and tliree 3-pointed teeth in the outer row. 

 Maxillary without teeth. Dentary with a graduated series of four or five 5- or 

 6-pointed teeth, followed by foiir or five minute ones on the sides. 



Gill-rakers 6+8. 



Anal sheath very short. Lateral line with pores developed on 7 or 8 scales. 



Origin of the dorsal half the length of the eye nearer to the caudal than to 

 the snout. Longest dorsal ray 4.7 in the length. Origin of the anal on the 

 vertical from the third or foiu-th scale behind the dorsal. Anal truncate, the 

 longest ray equal to the length of the base. Caudal shorter than the head, 

 4 in the length. Ventrals on the vertical from the first dorsal ray, very small, 

 reaching the thud or foiirth scale in front of the anal. Pectorals normal but 

 small, reaching the third to fifth scale in front of the ventrals. 



No humeral spot. Lateral stripe narrow, lead-gray, extending from the 

 humeral region to the triangular caudal spot. Caudal spot narrowed abruptly 

 behind and continued to the tips of the middle caudal rays. Dorsal, anal, 

 ventrals, and pectorals unmarked but somewhat dusky. Scales silvery below 

 the lateral line. 



3. Hasemania bilinbata ElHs. 

 Plate 31, fig. 3. 



Hasemania hilineata Ellis, Ann. Carnegie nius., 1911, 8, p. 150, pi. 1, f. 3. 



Habitat. — Rio Tiet6 Basin. 



