194 MEMOIRS OF THE CARNEGIE MUSEUM 



less than diameter of eye. Lateral shields small, of uniform height, height 2.5-3.3 

 in eye, hooks highest above tip of anal fin. Humeral process four times as long 

 as broad, spine-like. 



Sides and back covered with minute black dots, thickest at base of dorsal 

 and caudal fins, white underneath. 



63. Hemidoras carinatus (Linnaeus). 



Silurus carinatus Linnaeus, Syst. Nat., ed. 12,1,1766,504. — Bloch and Schnei- 

 der, Syst. Ichth., 1801, 108. 



Doras carinatus Lacepede, Hist. Nat. Poiss., V, 1803, 116 (Surinam). — Cuvier 

 and Valenciennes, Hist. Nat. Poiss., XV, 1840, 288, pi. 442 (Cayenne).— 

 Muller and Troschel, in Schomburgk, Reisen, III, 1848, 629 (Essequibo). — 

 Bleeker, Ichth. Arch. Ind. Prodr., I, 1858, 54; Nederl. Tijdschr. Dierk., I, 

 1863, 13 (name only); " Silures de Suriname," 1864, 31 (Surinam). 



Doras (Oxydoras) carinatus Kner, SB. Akad. Wiss. Wien, XVII, 1855, 144 

 (Surinam). 



Oxydoras carinatus Gunther, Catalogue, V, 1864,206 (Surinam; Essequibo River). — 

 Vaillant, Bull. Soc. Philom. (7), IV, 1880, 154 (Calderon). 



Hemidoras carinatus Eigenmann and Eigenmann, Proc. Cal. Acad. Sci., (2), I, 

 1888, 158; Occasional Papers Cal. Acad. Sci., 1, 1890, 258. — Eigenmann, Repts. 

 Princeton Univ. Exp. Patagonia, III, 1910, 394. 



Doras oxyrhynchus Valenciennes, in Humboldt, Rec. Obs. Zool., II, 1833, 184. 

 One hundred and thirty-three specimens, 44-320 mm. Tumatumari. (C. M. 



Cat. No. 1631o-2; I. U. Cat, No. 12025.) 



One specimen, 95 mm. Bartica. (C. M. Cat. No. 1632.) 



Ninety-two specimens, 48-267 mm. Rockstone. (C. M. Cat. No. 1633a-?; 



I. U. Cat, No. 12026.) 



Three specimens, 45, 113, and 247 mm. Georgetown market. (C. M. Cat. 



No. 1634a; I. U. Cat. No. 12027.) 



One hundred and sixteen specimens, 39-140 mm. Crab Falls. (C. M. Cat, 



No. 1635o-i; I. U. Cat. No. 12028.) 



Head 3.16-3.33; depth 4.25-4.5; D. 1,6; A. 11-14; lateral plates 33; eye 3- 



4.5 in the head, 1.5-2.75 in the snout, the snout proportionately longer in the 



old individuals; interorbital 1.3-1.5 in the eye. 



Heavy below the dorsal, the width 1.25 in the depth; caudal peduncle as 



wide as deep, its depth less than distance of anal from the lower caudal rays; 



occipital area roof-shaped, with a median groove which is not continued to the 



