Eigenmann: Nd.w Characins i\ Carnegie Museum. L79 



17. Astyanax gymnogenys sp. nov. 



Plate IX. 



and Cotype. — Two specimens. S7 mm. C. M. No. 3350. Porto I'niao, 

 lassu, Dec. 28, 1908. 



Head 3.8; depth 2.73; I). 11 or 12; A. 21-22; scales 6-4] 6; eye 

 3.2; interorbital equal to the snout, 3.5 ,v< s in the length of the head. 

 Compressed, subrhomboidal ; dorsal profile strongly arched, scarcely 

 depressed .1! the nape; preventral arch rounded, with a median series 

 of scales which may become regular in front; postventral area nar- 

 rowly rounded; predorsal area keeled, with a median series of 13 

 -cah~; occipital process one-sixth the distance from its base to the 

 dorsal, bordered by three scales on each side; interorbital but little 

 convex; frontal fontanel long and narrow, but shorter than the 

 parietal: snout small, the maxillary very broad and long, its length 

 3.5 4 in the head; second suborbital very narrow having a naked 

 area but one-third narrower than the bone; premaxillary with three or 

 lour teeth in the front series and five in the second; a single, small 

 concealed tooth on the maxillary. Mandible with three or four larger 

 teeth and two not very abruptly smaller ones; teeth of upper jaw 

 and larger ones of lower jaw tricuspid. Gill-rakers <s + 10; scales 

 regularly imbricate, no interpolated rows; lateral line little decurved; 

 caudal naked, anal sheath of a single series of scales along the anterior 

 rays, each scale with several radial stria'. Origin of dorsal nearer 

 caudal than to tip of snout, its highest ray 4.25 in the length; caudal 

 about 3.5 in the length; origin of anal about equ'distant from caudal 

 and base of pectoral; highest anal ray reaching to the base of the 

 penultimate ray or the last but four rays. Silvery, with brass} 

 luster: a very faint humeral bar; no caudal spot; caudal with its 

 margin and middle membranes dusky; anal dusky, the first ray and 

 tips ot the next two milk-white. 



Thisspeciesis very closely related to A. Eigenmanniorum, which in the 

 Rio Iguassu has either lost its caudal band or it has become very faint. 



[8. Deuterodon acanthogaster sp. nov. 

 Plate VII I, fig. 3. 



Type. — One specimen, 54 mm. C. M. No. 3395a. Corumba, April 27, 1909. 



Cotypes. — Eleven specimens. 41 to 55 mm. C. M. No. 3395&-J. Same place 

 and date. 



Colypes. — Six specimens, 35 to 52 mm. C. M. No. 3396. Rio Jauru, June 3, 

 1909. 



