28 MEMOIRS OF THE CARNEGIE MUSEUM. 



Range : Amazon basin. 



11087, I. U. M., one, 58 mm. Rio Jurua. From British Museum. 



6915a-i, C. M., four females, 47-55 mm., six males, 34-43 mm. Santarem, 

 Dec. 6, 9, and 15, 1909. Haseman. 



20713a-b, M. C. Z., two, 37 mm., Villa Bella. L. Agassiz. Thayer Expedition. 



20813a-f, M. C. Z., six, largest 51 mm. Iga. WiUiam James. Thayer Expe- 

 dition. 



20813a-d, C. M., four, largest 39 mm. San Joaquin, Bolivia, Sept. 4, 1909. 

 Haseman. 



Head 4.2-4.5; depth 4.2-4.5; D. 11; A. ^, ^, ^; scales 39-40, of which 10-12 

 with pores; eye 3 in head, snout 4 in head, interorbital slightly larger than eye. 



Maxillary always falling short of the third suborbital; maxillary-premaxillary 

 border three times in the head, in the largest specimen; premaxillary with six to 

 eight teeth; maxillary with ten to sixteen teeth on over half the length of the max- 

 illary; mandible with eight large teeth and eight small ones on the side. 



Margin of caudal and the middle rays dusky. In all other respects the 

 description of dentatus applies to this species. 



6. Aphyocharax erythrurus Eigenmann. 

 Aphyocharax erythrurus Eigenmann, Mem. Carnegie Mus., Vol. V, 1912, p. 313, 



PI. XLIV, fig. 4 (Rockstone, Crab Falls, and Maripicru Creek, British Guiana.) 



1879a, C. M., type. 1880a-e, C. M.; 12161, I. U. M., paratypes, 28-58 mm. 

 Rockstone. Eigenmann. 



1881a, C. M., paratype, 29 mm. Maripicru Creek. Grant. 



2494a, C. M., paratype, 35 mm. Crab Falls. Eigenmann. 



Head about 4; depth 3.66-4; D. 10 or 11; A. 17 or 18; scales 5-34 to 37^^-3; 

 nine to eleven scales with pores; eye a little longer than snout; 3.5 in the head; 

 interorbital 3 in the head. 



Maxillary-premaxillary border 2.5-2.75 in the head; six teeth in the pre- 

 maxillary, twelve to fourteen along the greater part of the maxillary, about thirteen 

 in the dentary. Middle caudal rays pale. 



This species is almost identical with alburnus, but can readily be distinguished 

 by the pale middle caudal rays and the slightly longer maxillary. 



7. Aphyocharax pusillus Giinther. 

 Aphyocharax pusillus Giinther, Proc. Zool. Soc. Lond., 1868, p. 245 (Huallaga; 

 Xeberos); Cope, Proc. Acad. Nat. Sci. Phila., 1871, p. 260 (Ambyiacu); Cope, 



" And a few on the caudal. 



