ElGENMANN : THE EXPEDITION TO BRITISH GUIANA. 21 



Astyanax abramoides sp. nov. 



Tetragonopterus abramis (non Jenyns) Gunther, Cat. Fish. Brit. 

 Mus. V, 321, 1864 (British Guiana; Essequibo); Steirid., Flussf. 

 Siidam. I, 8, 1879 (Orinoco, near Ciudad Bolivar). 



Type, 112 mm. (No. 1028 Carnegie Museum Catalog of Fishes.) 

 Tumatumari ,Potaro River. 



Cotypes, 86 specimens, 48-112 mm. Tumatumari. (C. M. Cat. 

 No. 1029, a-j ; I. U. Cat. No. 11727.) 



Cotypes, 2 specimens, 99-126 mm. Potaro Landing. (C. M. Cat. 

 No. 1030; I. U. Cat. No. 11728.) 



Cotypes, 27 specimens, 60-126 mm. Kangaruma, Lower Potaro 

 River. (C. M. Cat. No. 103 1, a-e ; I. U. Cat. No. 11729.) 



Cotypes, 48 specimens, 56-108 mm. Amatuk Cataract, Lower 

 Potaro River. (C. M. Cat. No. 1032, a-j ; I. U. Cat. No. 11 730.) 



Cotype, 1 specimen, 54 mm. Rockstone, Essequibo River. (C. 

 M. Cat. No, 1033.) 



Cotype, 1 specimen, 46 mm. Gluck Island at Rockstone. (C. 

 M. Cat. No. 1034.) 



Cotypes, 2 specimens, 56-63 mm. Wismar, Demarara River. (C. 

 M. Cat. No. 1035; L U. Cat. No. 11731.) 



Cotypes, 2 specimens, 51-64 mm. Christianburg, Demarara River. 

 (C. M. Cat. No. 1036; I. U. Cat. No. 11732.) 



Closely allied to anterior and abramis, but differing both in the 

 color of the caudal peduncle and caudal. 



Head 4 ; depth 2.4-2.5 ; D. 11 ; A. usually 28 ; 5 scales 9 or 10-43 



Elliptical, dorsal and ventral outlines similar, without prominent 

 humps ; the profile slightly depressed over the eyes. Preventral area 

 rounded, with small rather irregularly placed scales ; postventral area 

 narrowly rounded ; predorsal area narrow, with a linear median naked 

 area. 



Occipital process equal to one-fourth of the distance from its base 

 to the dorsal, bordered by four scales on its sides ; skull smooth in cross- 

 section, very convex ; interorbital much broader than the eye in adult ; 

 frontal fontanel a little narrower than the parietal ; margin of second 

 suborbital very convex, leaving a naked area, which is widest below ; 

 to 5 1 6 — 7 or 8 ; eye 2.5-3; interorbital 2.5-2.6. 



5 In those examined, one with 26, ten with 28, five with-29, three with 30. 

 6 In those examined one with 43, four with 44, two with 45, four with 46, four 

 with 47, one with 51. 



