THE AMERICAN TETRAGONOPTERINAE. 67 



or more in the head, equals interorbital ; profile not much depressed over eye; hum- 

 eral spot short, nearly equidistant from opercle and dorsal; depth 2.1-2.4; A. 26-30; 

 scales 7-33 or 35-5 or 6; highest dorsal ray usually not reaching adipose. 



6. chrysargyrea (Giinther). 

 ///. Maxillary with two teeth; maxillary longer than the distance from tip of snout to pupil; 

 eye 2.5 or more in the head, equals interorbital; the profile scarcely depressed; hum- 

 eral spot prolonged forward to a point; depth 2-f-; A. 26; scales 6-32-5; highest 



dorsal rays reaching the adipose 7. comma Eigenmann. 



66. Three and a half or four scales between the lateral line and ventrals. 



g. Six scales between the dorsal and the lateral line. Depth 2.3; no caudal spot, no 

 humeral spot; A. 26, lateral line 34; maxillary length equals distance from tip 

 of snout to pupil; third tooth of the anterior premaxillary series entirely withdrawn 

 from the line of the rest, forming a separate series; maxillary with 2 teeth; a black 

 line along base of anal; occipital process one fifth the distance from its base to the 



dorsal 8. melogramma Eigenmann. 



gg. Five scales between the dorsal and lateral line. 



h. A broad black band across the anterior part of caudal. A. 23-28; preventral area 



narrowly rounded (See also M. cotinho). 



i. Scales 5-29 to 32-4 9. oligolepis (Giinther) . 



ii. Scales 22-26, rarely 28 10. sanclae filomenae (Steindachner). 



hh. Caudal without black band. 



j. Some striae of the scales diverging from the middle line of each scale in nearly 

 opposite directions, up and down; eye 2.33-2.5 in the head, equal to the 

 interorbital; origin of dorsal directly over the origin of the ventrals; no 

 caudal spot in the adult; a round humeral spot. Anal usually 26-28, 

 emarginate; depth usually 2 (sometimes 2.4) scales 5-24 to 32-4. 



11. grandisquamis (Mttller & Troschel). 

 jj. Striae of the scales not as under j. 



k. Depth 2 in the length; anal not emarginate; dorsal rounded, the anterior 

 rays not much higher than the posterior, its origin behind that of the 

 ventrals. Eye 3 in the head, 1.33 in interorbital; scales 5-31—4 (to 

 ventrals); A. 27, its margin straight; head 3.66; depth 2; profile scarcely 

 depressed; maxillary with two teeth, extending somewhat beyond the 

 anterior margin of the eye; preventral area flat; a large caudal spot, not 

 extending to the end of the middle rays. 1 . . . . 12. ovalis (Giinther). 

 kk. Depth 2.2-2.6 in the length. Upper caudal lobe not black. 



I. Eye 2.4 or more in the head. 



to.. A. 30-33; scales 5.5-37-4.5; head 4.2-4.3; depth 2.4; interorbital 

 smaller than eye; a faint vertical humeral spot; tips of caudal 



and middle rays faintly dusky 13. barhouri Eigenmann. 



toto. A. 26; scales 5-32-4; head 3.33; depth 2.33; maxillary reaching to 

 near middle of eye; no caudal spot; humeral spot large, faint. 



14. xinguensis (Steindachner). 

 mmm. A. 23-24; scales 5-30 to 34-3; head 3.75-^; depth 2.3-2.6. Scales 

 with dark margins; a well-developed humeral spot. 



15. browni Eigenmann. 



II. Eye 2-2.2 in head; interorbital 2.4-3; scales 5-35^; head 3.6-3.7; depth 



2.5-2.66; 



1 Based on type in the British museum. 



