EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 185 



aaa. Caudal rounded; dorsal spine with a series of straight teeth along its anterior margin, its sides with 

 a regular or several irregular (in old), series of straight teeth, its posterior margin without teeth; 

 plates of sides of about the same height from dorsal to anal, those of opposite sides meeting along 

 the median line on upper and lower surfaces of the caudal peduncle of the adult; a narrow light 

 line from the upper margin of the eye to the caudal; a light line from dorsal spine forward to the 

 fontanel; nuchal region broadly rounded. (Acanthodoras) cataphractus. 



56. Doras granulosus Valenciennes. (Plate XVII, fig. 4.) 



Doras granulosus Valenciennes, in Humboldt, Rec. Obs. Zool., II, 1811, 184.— 



Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 1910, 392. 

 Pterodoras granulosus Bleeker, Nedeii. Tijdschr. Dierk., I, 1863, 15 (name only) 



" Silures de Suriname," 1864, 36 (Surinam). 

 Doras maculatus Valenciennes, in d'Orbigny, Voy. Am. Mer., V, ii, 1847, 7, 

 pi. 5, fig. 3. — Cuvier and Valenciennes, Hist. Nat. Poiss., XV, 1840, 281 

 (Buenos Ayres). — Muller and Troschel, in Schomburgk, Reisen, III, 1848, 

 629.— Steindachner, Denkschr. Akad. Wiss. Wien, XLI, 1879, 47 (Rio de la 

 Plata). — Eigenmann and Eigenmann, Proc. Cal. Acad. Sei., (2), I, 1888, 150 

 (Arary?); Occasional Papers Cal. Acad. Sci., I, 1890, 229 (Arary ?; Uruguay; 

 Buenos Aires, Serfa). 

 Doras murica (ex Natterer, MS.) Kner, SB. Akad. Wiss. Wien, XVII, 1885, 129 



(Cujaba). 

 Doras muricus Gunther, Catalogue, V, 1864, 202 (Demerara ?) . 



No specimens were secured. I have examined a specimen about 395 mm. 

 long collected by Schomburgk in Guiana. 



Head 4, depth about 4; D. 1,6; A. 11; plates 35; eye 3.5 in the snout, 10 

 in the head, 3.5 in the interorbital. 



Lateral plates beginning on the vertical from just in front of the dorsal, the 

 twelfth about equal to the eye in height, the highest on the caudal peduncle .4 

 the height of the peduncle, with a median but no lateral spines. Dorsal spine 

 nearly as long as the head, the spines of the posterior margin much longer than 

 those of the anterior; pectoral spine longer than the head, its posterior spines about 

 twice as long as its anterior; caudal forked, the lower lobe longer. Humeral spine 

 very slender, reaching to below the dorsal spine. Maxillary barbel reaching to the 

 tip of the pectoral ; free margin of the nasal plate but little pectinate. 

 Chocolate, marbled; the fins spotted. 



57. Doras costatus (Linnaeus). 



Silurus costatus Linnaeus, Syst. Nat., ed. 12, I, 1766, 506. 

 Cataphractus costatus Bloch, Ausl. Fische, VIII, 1794, 82, pi. 376. 



