258 CALIFORNIA ACADEMY OF SCIENCES. 



Hemidoras humeralis Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



i, 158, 1888. 

 Habitat: Eio Negro. 



199. Hemidoras carinatus. 



Silurutf carinatus Liuufeus, Syst. Nat. ed. xii, i, .'304, 1766. Bloch it 



Schneider, " Systema Natura, 108," 1801. 

 Doras carinatus Lacepede, Hist. Nat. Poiss. v, 116, 1803 (Siirinain); 



Cviv. & Val. XV, 288, pi. 442, 1840 (Cayenne); Miiller & Troschel, 



Schomburgk, British Guiana, 629, 1848 (Esseqiiibo); Bleeker, 



Ichthyol. Arch. Indici Siluri 54, 1858; id. Nederl. Tijdschr. 



Dierkiaude, i, 13, 1863 (name only); id. Silures de Suriuanie, 



31, 1864 (Surinam). 

 Doras (Oxydorus) carinatus Kner, SB. Ak. Wien, xvii, 144, 188."> 



(Surinam). 

 Oxydoras carinatus Gitnther, Cat. Fish. Brit. Mus. v, 206, 1864 



(Surinam; Essequibo Kiver); Vaillaut, Bull. Soc. Philom. series 



7, iv, 154, 1880 (Calderon). 

 Hemidoras carinatus Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. 



i, 158, 1888. 

 Doras oxyrhynchus Val. "Humb. Observ. Zool ii, 184, 1833." 

 Habitat: Guianas, Calderon. 



200. Hemidoras orestes. 



Oxydoras orestes Steiudachner, SB. Ak. Wien, Ixxi, 138, pi. i, 187"> 



(Xingu, Brazil). 

 Hemidoras orestes Eigenm. <fe Eigenm. Proc. Cal. Acad. 2d Ser. i, 



158, 1888 (Huytahy), 

 Habitat: Xingu; Huj'tahy. 



This species is known to us from 4 specimens .05-. 10 

 m. long. Huytahy. 



It agrees very closely with affinis, which should per- 

 haps be considered but a variety of 0. orestes. The only 

 noticeable differences are set forth in the key. 



201. Hemidoras affinis. 



Oxydoras f(/A"«/.s- Steindachner, Flussfische Sitdam. ii, 7, pi. i, fig. 1, 



1881 (KioPuty). 

 Hemidoras affinis Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. i, 158, 



1888 (Eio Puty). 

 Habitat: Eio Puty. 



Body subterete, tapering backward, the depth every- 

 where greater than the width. Head rather long; higher 

 than wide, the snout long and pointed, the profile not 



