eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 207 



Family IV. HELOGENEIDJE Fam. nov. 



< Siluridce anomalopterce Gunther, Catalogue, V, 1864, 3, part. 



Dorsal small, behind the middle of the body; anal long, its origin near the 

 beginning of the fifth ninth of the body; dorsal and pectoral without spines; adi- 

 pose fin minute; caudal forked; gill-membranes free from the isthmus; teeth few; 

 six barbels; nares without barbels; eyes very small, directed upward and outward; 

 air-bladder transversely uniform, not covered by bone. 



So far known from one genus. 



Helogenes Gunther. 



Helogenes Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 {marmoratus). 



Type, Helogenes marmoratus Gunther. 



This genus agrees with Hypophthalmus in its long anal and the backward 

 position of the dorsal, but differs from it in so many other essential characters that 

 it is but remotely related to that genus. 



Upper jaw heavy, the snout rounded, lower jaw included; vomerine teeth in 

 two separate patches; upper jaw with two series of teeth, the inner obscure; lower 

 jaw with a narrow band of teeth, some of the outer ones distinctly larger than the 

 rest; head bullet-shaped, the eyes on side of head, superior; barbels not margined, 

 the two mental barbels remote from each other, below the angle of the mouth ; gill- 

 membranes overlapping; about twelve branchiostegals ; gill-rakers very short; 

 fontanel reaching to the base of the occipital process; coalesced vertebrae with 

 broad lateral processes; no dorsal or pectoral spines; eye without a free orbital 

 margin; anal very long. 



78. Helogenes marmoratus Gunther. (Plate XXII, fig. 2.) 

 "Asicurrupa" (of the natives about the Kaieteur). 



Helogenes marmoratus Gunther, Ann. and Mag. Nat. Hist., (3), XII, 1863, 443 

 (Essequibo); Catalogue, V, 1864, 66 (Essequibo). — Eigenmann, Repts. Prince- 

 ton Univ. Exp. Patagonia, III, 1910, 398. 

 This species has been taken but once before. 

 Fifteen specimens, 39-82 mm. Creeks about Aruataima. (C. M. Cat. No. 



1703a-c; I. U. Cat. No. 12085.) 



Nineteen specimens, 39-71 mm. Creeks about Holmia. (C. M. Cat. No. 



1704a-c; I. U. Cat. No. 12086.) 



Eleven specimens, 68-86 mm. Potaro Highland. (C. M. Cat. No. 1705a-c; 



I. U. Cat. No. 12087.) 



