258 CALIFORNIA ACADEMY OF SCIENCES. 



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



i, 158, 1888. 

 Habitat: Kio Negro. 



199, Hemidoras carinatus. 



tiilurus carinatus LiumBus, Syst. Nat. ed. xii, i, 504, 1766. Bloch & 



Schneider, " Systema Natura, 108," 1801. 

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



Cuv. & Val. xv, 288, pi. 442, 1840 (Cayenne); Miiller & Troschel, 



Sehomburgk, British Guiana, 629, 1848 (Essequibo); Bleeker, 



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



Dierkunde, i, 13, 1863 (name only); id. Silures de Suriname, 



31, 1864 (Surinam). 

 Doras (Oxydoras) carinatus Kner, SB. Ak. Wien, xvii, 144, 1885 



(Surinam). 

 Oxydoras carinatus Giinther, Cat. Pish. Brit. Mus. v, 206, 1864 



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



7, iv, 154, 1880 (Calderoii). 

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



i, 158, 1888. 



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

 Habitat: Guianas, Calderon. 



200, Hemidoras orestes. 



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



(Xiugu, Brazil). 

 Hemidoras orestes Eigenm. & Eigenin. Proc. Cal. Acad. 2d Ser. i, 



158, 1888 (Huytahy), 

 Habitat: Xingu; Huytahy. 



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 affinis Steindachner, Flussfische Sudani, ii, 7, pi. i, fig. 1, 



1881 (Rio Puty). 

 Hemidoras affinis Eigenm. & Eigenm. Proc. Cal. Acad. 2d Ser. i, 1.18, 



1888 (Rio Puty). 

 Habitat: Rio 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 



