5d. Lateralis. With three black spots on each side. 3d. Zeu- 

 cO'jitera. All the fins pale and whitish. 



72d Species. Silvery Catfish. Pimelodus argyrus. Pirn- 

 elode argyre. 



Jaws nearly equal, lateral barbs brown and reaching the pec- 

 toral fins. Eyes elliptical. Body silvery, lateral line straight. 

 Fins brownish, anal with 25 rays. Tail equally forked. 



Silurus argenteus. Monography, sp. 4. There is another 

 species of that name alre:idy. 



A small ami rare species, Very similar to the foregoing, of 

 which it is perhaps a variety. Number of rays similar. 



2d Section. Leptops. Tail bilobed. Eyes round and very 

 small. Nine abdominal rays. Vent posterior. Adipose fins 

 large. 



73d Species. Clammy Catfish. Pimelodus viscoeiis. Pim- 

 elode visqueux. 



Jaws nearly equal, barbs very short, eyes round over the 

 head. Body entirely brown, lateral line raised upwards before. 

 Pectoral fins with 1 and 7 rays, anal fin rounded with 1 5 rays. 

 Tail unequally bilobed and black, upper lobe smaller and white. 



Silurus -viscosu^. Monogr. sp. 6 



A very singular and rare species, found at the falls. Length 

 only 4 inches, brown with bluish and greyish shades, covered 

 with a clammy viscosity; throat whitish. Head very flat, with 

 a longitudinal furrow above, elongated; upper jaw hardly long- 

 er. Eyes over the head very small and bluish. Spines of the 

 anterior fins short, thick, and simple. Dorsal with 1 and 7 rays. 

 Abdominal small with 9. Anal blackish. 



75th Species, Clouded Catfish. Pimelodus nebulosus. 

 Pimelode nebuleux. 



Jaws equal, barbs shorter than the head. Eyes round, ex- 

 ceetUngly small. Body olivaceous, clouded with pale brown, 

 white beneath, lateral line nearly straight. Pectoral fins with 

 1 and 9 rays, anal fin rounded with 12 rays. Tail merely 

 l^otched, hardly but equally bilobed. 

 Silurus nebulosna. Monogr. sp. 5. 



This species is totally ditrerent from the foregoing, and 

 might perharjs form a peculiar section or even subgenus, (O- 



