152 CALIFORNIA ACADEMY OP SCIENCES. 



109. Pimelodella wesselii. 



Pimdodus (Pseudorhamdla) weaselii Steiudachuer, SB. Ak. Wieu, 



Ixxiv, Nov. 1876. Fhassfische sudustl. Bras, iii, 56, foot note 



(Esseqiiibo). 

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



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



Santareni). 

 Habitat: Rio Puty to Eio Essequibo; Amazou from Para to Cudajas. 



This species is very closely related to cristatus; wheii 

 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 Ih in its length, its greatest depth 1|; oc- 

 cipital crest striate, its greatest width 2i to 3 in its 

 length. Distance between covered with very thin 

 skin, anterior and posterior nares li 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 1|— If in snout, 4 in head, 1-11 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 3h 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 l-ll 

 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 2| 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. 



