53. PIMELODUS. 115 



C. The occipital process does not extend on to the basal bone of the 



feeble dorsal spine ; adipose fin longer than dorsal ; body elongate : 

 Rhamdia, Bleek. 



1. American species. 



a. Dorsal fin with six soft rays. 



a. The adipose fin is one-third, or more than one-third, of the 

 total length (without caudal). 

 aa. The maxillary barbels extend considerably beyond the origin 



of the adipose fin, p. 119. 

 bb. The maxillary barbels extend to, or nearly to, the origin of 

 the adipose fin, p. 123. 

 /9. The adipose fin is less than one-third of the total length (with- 

 out caudal). 

 aa. The tail above the anal fin is almost as high as the trunk, 



p. 126. 

 bb. Tail gradually becoming lower from its commencement, 

 p. 128. 



b. Dorsal fin with seven or eight soft rays, p. 131. 



2. Non- American species, p. 133. 



D. The occipital process does not extend on to the basal bone of the 



dorsal spine ; body short, stout : Pseudopimelodus, Bleek., p. 133. 



E. The occipital process is short ; body moderately elongate ; adipose fin 



not longer than dorsal : Amphilius, m., p. 134. 



A. Head granulated above ; dorsal spine strong. 



1. Pimelodus maculatus. 



? Seba, iii. 29. 4. 



? Mystus, sp., Gronov. Mus. Ichth. i. no. 84, and Zoophyl. no. 385. 



Pimelodus maculatus, Lacep. v. pp. 94, 107; d'Orb. Voy. Amer. Mend. 



Poiss. Atl. pi. 1. fig. 1 (not good) ; Cuv. 8f Vol. xv. p. 192 ; Kner, 



Sitzgsber. Wien. Acad, xxvii. p. 413. 

 ? Mystus ascita, Gronov. Syst. ed. Gray, p. 156 (not Silurus ascita, L.). 

 Pseudorhamdia ascita, Bleek. Versl. 8f Meded. Acad. Wet. Amsterd. 



1862, xiv. p. 384. 



D. 1/6. A. 12. P. 1/0. Vert. ^- 4 . 



Head bony above, granulated ; occipital process convex, obtusely 

 keeled, subtriangular, with the apex truncated, much longer than 

 broad, joining the large saddle-shaped bone at the base of the dorsal 

 spine. The maxillary barbel is as long as the fish. The length of 

 the adipose fin is one-fifth of the total (without caudal). Dorsal and 

 pectoral spines very strong, nearly equal in length, as long as, or 

 longer than, the head ; the pectoral spine is serrated. Caudal deeply 

 forked. 



Brazil, Surinam. 

 a. Adult. River Capin, Para. Purchased of Mr. Stevens. 

 6, c, d, e-f. Adult and half-grown. Surinam. 



g. Adult. Surinam. Purchased of Mr. Frank (=Ps. ascita, Blkr.). 

 h-i. Half-grown. Demerara. Presented by Dr. Hancock. 

 Tc-l. Adult. Baranquilla, New Granada. From Mr. Rippon's Col- 

 lection. 



