152 CALIFORNIA ACADEMY OF SCIENCES. 



109. Pimelodella wesselii. 



Pimelodus (Pseudorhamdia) wesselii Steindachner, SB. Ak. Wien, 



Ixxiv, Nov. 1876. Flussfische siidostl. Bras, iii, 56, foot note 



(Essequibo). 

 Pimelodella wesselii Eigeum. & Eigenm. Proc. Cal. Acad. 2d Ser. 



i, 132, 1888 (Cudajas; Para; Marajo; Rio Madeira; Kio Puty; 



Sautarem). 

 Habitat: Kio Puty to Kio Essequibo; Amazon from Para to Cudajas. 



This species is very closely related to cristatus', when 

 the color is obliterated they can scarcely be distinguished. 



Body elongate, strongly compressed. Head rounded, 

 obtusely conical, covered with very thin skin on the top; 

 greatest width 1J in its length, its greatest depth If; oc- 

 cipital crest striate, its greatest width. 2 J to 3 in its 

 length. Distance between covered with very thin 

 skin, anterior and posterior nares 1^ in the eye. 



Maxillary barbel reaching tip of adipose fin or beyond 

 the tips of the middle caudal rays; mental barbels to 

 base of pectoral; postmental about to tip of pectoral. 



Eye l|-lf in snout, 4 in head, 1-1 i in interorbital, 1 

 diameter behind the rictus. 



Width of mouth 3 in head; teeth of the upper jaw 

 slightly smaller than those of the lower, the width of 

 the upper band 3 in head. 



Gill-membranes separate to below anterior portion of 

 eye; gill-rakers about as long as diameter of pupil, 3+6-9. 



Dorsal spine high and slender, very small recurved 

 hooks on the upper half of both margins, its height 1-11 

 in head; highest rays about one-sixth longer than head; 

 the dorsal spine inserted about midway between snout 

 and anal. Adipose fin beginning immediately behind 

 first dorsal, about 2J in the length. 



Caudal deeply forked, one of the rays sometimes pro- 

 duced in a filament, sometimes the upper, sometimes the 

 lower lobe longer always longer than head. 



Anal rather high, the highest ray If in head, its tip 

 not reaching the end of the adipose. 



