eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 363 



breast ctenoid, those of the sides cycloid in young, becoming ctenoid in adult; 

 lateral line always complete, a long tube extending on the middle caudal membrane; 

 caudal naked; maxillary with none or two teeth; a series of tricuspid teeth in the 

 premaxillary and an inner series of five-pointed ones, the denticles of which are 

 arranged in a U-shaped curve; predorsal area scaled. 



Premaxillary teeth in parallel series, the third tooth of the first series not being 

 out of line with the rest. 



One species is found in the Guianas. 



220. Ctenobrycon spilurus (Cuvier and Valenciennes). (Plate XLVII, fig. 1.) 

 Tetragonopterus spilurus Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 

 156 (Surinam). — Gunther, Catalogue, V, 1864, 318. — Eigenmann and Eigen- 

 mann, Proc. U. S. Nat. Mus., XIV, 1891, 52.— Ulrey, Ann. N. Y. Acad. Sci., 

 VIII, 1895, 274. 

 Ctenobrycon spilurus Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

 1910, 435. 



Several hundred specimens, the largest 77 mm., from the trenches of George- 

 town and the Botanic Garden. (C. M. Cat, No. 1425 and 1426.) 



Head 4.25-4.5; depth 2.25-3; D. 11; A. usually 41-45 53 ; scales 11 or 12-41 to 

 50-7 to 10; eye 2.75-3. 



Deuterodon Eigenmann. 

 Deuterodon Eigenmann, Ann. Carnegie Mus., IV, 1907, 140, pi. 41, fig. 3 (iguape). 

 Joinvillia Steindachner, Wien Anz. Akad.-Wiss., XIV, 1908, 30 (rosce). 

 Type Deuterodon iguape Eigenmann. 



Compressed, elliptical fishes of small size, 54 most nearly related to Astyanax, 

 from which they differ in dentition. Teeth all multicuspid incisors, those in the 

 premaxillary in two series, those in the maxillary (2-7) and in the mandible in a 

 single series, the latter graduate; lateral line complete; caudal naked. Lives 

 largely in cataracts. 



Key to the Guiana Species of Deuterodon. 



a. Each pore of the lateral line surrounded by black potaroensis. 



aa. A black median band or line, usually with pinnately diverging lines pinnatus. 



221. Deuterodon potaroensis Eigenmann. (Plate LIII, fig. 1.) 

 Deuterodon potaroensis Eigenmann, Ann. Carnegie Mus., VI, 1909, 27; Piepts. 

 Princeton Univ. Exp. Patagonia, III, 1910, 431. 



63 Of those examined one has 36, one has 39, one has 40, three have 41, seven have 42, four have 43, 

 four have 44, three have 45, one has 46, and one has 47 anal rays. 

 54 The greatest recorded length is about 13 cm. over all. 



