si. OXVUtlRAS. 20? 



lower surfaces. Humeral process striated, obtuse behind, nearly halt 

 as broad as long. Eye rather hirge, its diameter being much longer 

 than its distance from the posterior nostril. The bases of the barbels 

 are united by a membrane fringing tlie lower jaw ; those of the 

 maxillaries are provided with small tentacles, and extend to below 

 the eye. No teeth in the upper jaw ; those of the lower quite rudi- 

 mentary. Unifonn brownish above, Avhitish below. (Kner.) 

 Barra do llio Negro. 



3. Oxydoras pimctatus. 



Doras punctatus, Kner, Sitzr/shcr. Wioi. Acad. 18o5, x\\\. p. 136. fig. 10. 

 Corj'doras pimctatus, Hyrtl, DodscJu: Acrid. TI'Us. Wien, 1859, xvi. 

 p:i7. 



D. 1/6. A. 13. P. 1/7. Y. 7. L. lat. 28-29. Vert. 6/2l. 



Adipose fin short. Lateral shields rather small, half covered with 

 thin skin, and with the hind margins serrated. Tail without shields 

 on its upper and lower surfaces. Humeral process obliquely trun- 

 cated behind, not much broader than the pectoral spine. Eye rather 

 large, its diameter being equal to its distance from the anterior 

 nostril. Barbels provided with tentacles : those of the maxillaries 

 do not extend backwards to the gill-opening ; the mandibulary 

 barbels are united at the base by a membrane, and sometimes one 

 or two are bifid. A narrow band of small teeth in the lower jaw. 

 the teeth of the upper being scarcely visible, if present. Upper 

 parts of the body and the fins with small blackish spots. {Kner.) 



Matogrosso ; Rio Guapore. 



4. Oxydoras brevis. 



Doras brevis (Heckel), K)ier, Sitzgsber. Wien. Acad. 1855, xvii. p. 138. 

 fig. 11. 

 D. 1/6. A. 13-14. P. 1/7. T. 7. L. lat. 29-30. 



Lateral shields of moderate size, not (|uitc half as high as the body. 

 each with a scries of spines along its hinder margin. Humeral pro- 

 cess obliquely truncated behind, much broader than, and extending 

 beyond tlie middle of, the pectoral spine : its point is not much more 

 distant from the root of the caudal fin than from the end of the 

 snout. The upper and lower sm-fiices of the tail are not shielded. 

 Adipose fin as long as anal, without spinous ray. Eye rather large. 

 Barbels short, provided with tentacles ; the four mandibulai-y barbels 

 united by a membrane at the base. Veiy small teeth in the lower 

 jaw only, none in the upper. Reddish brown above, whitish below. 

 {Kner. ) 



Barra do Rio Negro. 



5. Oxydoras fimbriatus. 



Doras fimbriatus, Ktwr, Sitzi/sbci: Win). Acad. 1855, xvii. p. 134. tig. 5. 

 D. 1/6. A. 11. p! 1/8. V. 7. L. lat. 29-30. 

 Adipose fin short. Lateral shields high, with the hind margins 



