THE AMERICAN TETRAGONOPTERINAE. 271 



Key to the Species of the Subgenus Astyanax. 



"Scales S to 10-50 to 55-8 or 9; A. 22-25; frontal fontanel not much shorter than the parietal; one 



tooth on the maxiUary 30. microlepis Eigenmann. 



aa. Scales 8 or 9-43 to 45-7 or 8; A. 27; frontal fontanel 2.5 in the parietal; no ma.xillary teeth. 



31. cordovae (GUnther). 

 aaa. Lateral line rarely with more than 39 scales, 41 in some specimens of A. fasciatus, A. gymnogenys, 

 A. taeniatus, and .4. scabripinnis. 

 b. Dark stripes between the rows of scales on the sides; a dark band along caudal peduncle con- 

 tinued to the end of the middle rays; A. 26-28; scales 6 or 7-34 to 38-5; depth 2.8. 



32. lineatus (Perugia). 

 66. No lateral stripes. Usually a silvery band, 

 c. Second suborbital not covering entire cheek. 



d. Anal with 25 or more rays {A. laticeps 24-25; A. eigenmanniorum and A. ruberrimus 23-28; 

 A. fischeri 23-29; A. ribeirae 23-27; A. multidens 24-25). 

 e. An elongate humeral spot. 

 /. Depth 3 in the length; pectorals not reaching ventrals. Scales 7-34 to 38-6. Scales 

 in 14 rows. Dorsal fin behind the base of the ventrals. Maxillary with one tooth, 

 extending a little beyond the anterior border of the eye to end of first suborbital; 

 interorbital space much greater than the eye, very convex; eye 4 in head; head 3f ; 

 depth 3; A. 27 or 28. A humeral spot twice as long as high. 



33. wappi (Cuv. & Val.). 

 //. A conspicuous projectile-shaped humeral spot, the blunt end forward. Depth 2.3- 

 2.6; scales 6-34 or 35-5; A. 25 or 26; eye 2.7 in the head; interorbital 3-3.5. 



34. mucronatus Eigenmann. 

 ee. Humeral spot diffuse, (or absent), vertically elongate. 



' g. Snout very blunt, rounded; maxillary more than 2 in tlic snout and eye. 



h. Snout half as long as the eye; 5 teeth in the front row of the premaxillary; depth 



2.4; eye 2.4; A. 28; scales 6-35-4 35. breeirhiuun Eigenmann. 



hh. Snout more than half the length of the eye; 2 or 3 teeth in the front series of the 

 premaxillary; a caudal band; depth 2.5-2.6; eye 2.5; A. 23-24; scales 5-35-4. 



36. gilon, Eigenmann. 

 gg. Snout more or less pointed, the mouth terminal. 

 i. No caudal spot; cheek narrowly naked. 

 j. A. 31; depth 2.4; scales 8-35-7; maxillary with 4 teeth; a diffuse humeral 



band 37. daguae Eigemiiann. — 



jj. A. 30; depth 2.8; maxiUary without teeth, a rounded humeral spot. 



38. longior (Cope). 

 ijj. A. 27 or 28; depth 2.8-3.2; maxillary with one small tooth. 



39. marionie Eigenmann. 



>ii. Caudal spot rounded, not continued to the end of the middle rays. 

 X k. A. 23-28; eye 3 in the head, 1.2 in the interorbital; maxillary equals snout; 



J .„'.':' depth 2.2-2.75; caudal spot conspicuous, across the entire caudal ^ Q_ '' 



^ peduncle in the younger 40. ruba-rimus ' Eigenmann. - ^ 



kkk. A. 23-27; eye 2.75-3, equal to the interorbital or greater; scales 6 or 7-34 

 to 38-5 or 6; caudal spot at least as large as eye; depth 2.5-3. 



41. ribeirae Eigenmann. 

 Hi. A black caudal band extending to the end of the middle rays. 



I. Dorsal from nearly an orbital diameter to several nearer the snout than 

 the base of the middle caudal rays. 

 m. Four or five teeth in the inner scries of the premaxillary; no humeral 

 spot; a band from above the origin of the anal obliquely to the end 

 of the middle caudal ray and the three rays above it; depth 2.5; 

 eye 3.5-3.7; maxillary with one tooth, a little longer than eye; 

 A. 25-30; scales 8 or 9-40 or 41, 6 or 7. . . .42. melae Eigenmann. 



' Based on specimens from the Pacific slope of Colombia. Specimens from Panama have A. 23- 

 29; eye 3-3.2, 1-1.25 in the interorbital; maxillary equals snout; caudal spot well defined, oval; scales 

 6 or 7-34 to 37-5 to 7; depth 2 66-3. 



