eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 397 



Head 4.5; depth 3.5-4; D. 12; A. 33-40. 



Similar to Cynodon gibbus in general appearance. 



Although reported as occurring in all the rivers of Guiana no specimens of this 

 species were seen. A specimen 228 mm. long in the British Museum was presented 

 by Robert Schomburgk. Another over 500 mm. long is in the Berlin Museum. 

 It would seem from these specimens that the caudal is slightly emarginate. 



Mr. Ellis has recently taken one on Gluck Island. 



Subfamily Characin^e. 

 Exodon M tiller and Troschel. 

 Exodon MtJLLER and Troschel, Horse Ichth., I, 1845, 31 (paradoxus). 

 Hystricodon Gunther, Catalogue, V, 1864, 549 (paradoxus). 

 Type, Exodon paradoxus Mtiller and Troschel. 



Entire dorsal in front of the vertical from the anal; anal moderate; lateral 

 line complete; teeth conical, in a double series in the mandible, those of the outer 

 series largest, irregular, divergent; a pair of large tooth-like prongs extending 

 forward on tip of snout. 



253. Exodon paradoxus Mtiller and Troschel. (Plate LX, fig. 1.) 



Exodon paradoxus Muller and Troschel, Horse Ichth., I, 1845, 31, pi. 4, fig. 1 

 (Essequibo); in Schomburgk, Reisen, III, 1848, 635 (Upper Rupununi). — 

 Kner, "Familie der Characinen," ii, 1859, 38 (Rio Branco). — Eigenmann 

 and Eigenmann, Proc. U. S. Nat. Mus., XIV, 1891, 58. — Eigenmann, Repts. 

 Princeton Univ. Exp. Patagonia, III, 1910, 446. 



Epicyrtus paradoxus Castelnau, Anim. Am. Sud, Poiss., 1855, 60 (Caixas; Ara- 

 guay; Amazon). 



Epicyrtus exodon Cuvier and Valenciennes, Hist. Nat. Poiss., XXII, 1848, 46. 



Hystricodon paradoxus Gunther, Catalogue, V, 1864, 349. 



One specimen, 75 mm. Rupununi. (C. M. Cat. No. 2145.) 



This species differs from all other characins in its large black spots on the 



side in front of the dorsal and covering the caudal peduncle. 



Head 3.5; depth 2.75-3; D. 10 or 11; A. 19-22; scales 9-36-6. Eye 1 in 



snout, 3.5 in head, 1.5 in interorbital. 



Dorsal and ventral profiles equally arched, without humps or depressions; 



ventral area rounded, without a distinct median series of scales; predorsal area 



rounded, with a median series of about eleven scales. Occipital process extending 



one-sixth of the way to the dorsal ; fontanel reaching to above the middle of the eye ; 



