254 CALIFORNIA ACADEMY OF SCIENCES. 



few imbedded plates in front of a large scute which con- 

 nects the humeral process and dorsal plate, the following 

 lateral scutes much lower, each with a large median hook, 

 and a series of fine marginal teeth above and a series of 

 one large and several fine teeth below the median hook; 

 the lateral scutes on the caudal peduncle have a more 

 enlarged median hook, and the fine marginal teeth fewer 

 or none. No plates on dorsal or ventral surfaces. 



Distance of the dorsal spine from the snout 2J 2-| in 

 the length; dorsal spine slightly curved, its sides rather 

 deeply grooved, its anterior margin with rather long and 

 fine teeth to near the tip, its posterior margin with short 

 wide-set teeth. Space between dorsal and adipose fins 

 3i-4 in the length; adipose fin as high as long, half as 

 long as the dorsal fin. 



Caudal deeply emarginate, upper lobe longer, 3J in 

 the length. Anal fin about as high as long, rounded. 



Ventrals short, not reaching to the anal. 



Pectoral spine strong, longer than the dorsal spine, 

 reaching beyond base of ventral fins; both margins ser- 

 rate, both surfaces striate. In a specimen .05 in. long 

 the pectoral spine is as long as the dorsal spine, and 

 does not reach to the base of the ventrals. 



Light brown above, silvery below the lateral scutes; tip 

 of dorsal, anterior half of anal and the pectoral fins 

 sometimes dotted with dark. 



Head 3|-3f; depth 3J ; lat, 1. 30-31+2 or 3; D. I, 6; 

 A. 12; V. 7; P. I, 8. 



Six specimens .05-. 13 in. Tabatinga; Jutahy; Coary; 

 Teffe. Agassiz, James, Thayer and Talisman. 



190, Hemidoras brevis, 



Doras breviit Kuer, SB. Ak. Wieu, xvii, 138, pi. vi, fig. 11, 1855 



(Barra do Rio Negro). 

 Cory dor as brevis Heckel MS. Kner, 1. c. 

 Oxydoras brevis Giinther, Cat. Fish. Brit. Mus. v, 207, 1864 (copied); 



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



