eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 317 



tooth on each side of each jaw, similar to, but narrower than, those of the inner 

 series; two similar teeth on the maxillary and seven similar ones on each side of the 

 lower jaw; cheeks narrow, entirely covered by the suborbitals. 



Scales thin, cycloid, deeply imbricate, with few (or more frequently no) radial 

 striae; caudal and anal naked; lateral line complete, decurrent; dorsal short, its 

 length less than half its height, which is 6.75 in the length; lower caudal lobe the 

 longer, 4.5 in the length; origin of anal under origin of dorsal or a little farther 

 forward; ventrals small, not reaching anal, in contact along their inner margin 

 when closed; pectorals large, directed downward and backward when closed, the 

 tips projecting beyond the ventral profile, not reaching the ventrals; when opened 

 the margins of the pectorals are in one plane. 



Iridescent, the middle caudal rays dusky, otherwise without marking. 



Subfamily Agoniatin^e. 

 Agoniates Muller and Troschel. 



Agoniates Muller and Troschel, Hor. Ichth., I, 1845, 33 (halecinus). 



Type, Agoniates halecinus Muller and Troschel. 



Breast trenchant, not expanded; maxillary and mandible with a single series, 

 premaxillary with two series of teeth, those of the inner series of the premaxillary 

 tricuspid; a large canine on the mandible on each side anteriorly, received in a 

 groove on the palate; a few minute tricuspid teeth between the anterior canine 

 teeth, a pair of conical teeth within the outer series in front; seven or eight conical 

 teeth on the side of the lower jaw behind the fangs, the third largest; cheeks 

 entirely covered. 



A genus of one species. 



172. Agoniates halecinus Muller and Troschel. 



Agoniates halecinus Muller and Troschel, Horae Ichth., I, 1845, 33, pi. 7, fig. 2 

 (Guiana); in Schomburgk, Reisen, III, 1848, 636 (Cuyuni). — Cuvier and 

 Valenciennes, Hist, Nat, Poiss., 1848, 347— Gunther, Catalogue, V, 1864, 

 344. — Eigenmann and Eigenmann, Proc. U. S. Nat, Mus., XIV, 1891, 57 — 

 Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 440. 

 Head 4.66 in the length; depth somewhat less than the length of the head; 



A. 30; lateral line 39, silvery. 



This species, which greatly resembles Hydrolycus scomberoides, is known from 



the type only, about 100 mm. long, in the Berlin Museum. 



