eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 313 



Compressed, preventral and predorsal areas rounded, the latter with a median 

 series of ten scales. 



Mouth large, the antero-posterior extent of the premaxillary very short, the 

 maxillary with a curved anterior margin, its length about equal to that of the eye; 

 about twelve teeth in each premaxillary; maxillary with about four similar teeth; 

 about twenty teeth on each side of the lower jaw. 



Scales cycloid, regularly imbricate, six scales with pores; caudal naked. 



Ventrals just reaching anal; pectorals not reaching the ventrals. 



Very few color-cells on the sides; scales of the back margined with dusky; 

 upper part of the first few dorsal rays black. 



Three small specimens (C. M. Cat. No. 1891; I. U. Cat. No. 12163) probably 

 belong to this species. 



168. Aphyocharax erythrurus sp. nov. (Plate XLIV, fig. 4.) 



Type, 57 mm. Rockstone sand-bank. (Carnegie Museum Catalog of 

 Fishes No. 1879.) 



Cotypes, thirty-seven specimens, 28-58 mm. Rockstone sand-bank. (C. M. 

 Cat, No. 1880a-e; I. U. Cat. No. 12161.) 



Cotype, one specimen, 29 mm. to base of caudal. Maripicru Creek. (C. M. 

 Cat, No. 1881a.) 



Cotype, one specimen, 35 mm. Crab Falls. (C. M. Cat. No. 2494.) 



Head about 4; depth 3.66-4; D. 10 or 11; A. 17; scales 5-34 to 37-3 36 ; nine 

 to eleven scales with pores; eye in adult a little longer than snout, 3.5 in the 

 head; interorbital 3 in the head. 



Elongate, preventral area with a median series of about thirteen scales; pre- 

 dorsal area with a median series of fourteen scales, the series irregular anteriorly; 

 head somewhat blunt, the mouth terminal, oblique; maxillary-premaxillary border 

 forming a continuous curve, its length 2.5 in the length of the head; six teeth in 

 each premaxillary; about thirteen in each dentary, and about twelve to fourteen 

 along the greater part of the maxillary. 



Scales regularly imbricate, each scale of half-grown specimens with a median 

 fifth free from striae, above and below this with numerous parallel horizontal lines; 

 anal and caudal naked. 



Dorsal behind the ventrals; caudal deeply forked; anal emarginate; ventrals 

 not reaching anal; pectorals not emarginate; pectorals not to ventrals. 



Straw-colored; a diffuse humeral spot; caudal brick-red in life. 



36 And a few small ones on the caudal. 



