118 silurid.*:. 



interorbital space. Dorsal fin somewhat higher than long ; its spine 

 is slender, a little more than half as long as the head, and somewhat 

 shorter than that of the pectoral fin. Caudal fin forked, with the 

 upper lobe longer. Coloration uniform. 



Esmeraldas. 

 a-b. Types of the species. Purchased of Mr. Fraser. 



6. Pimelodus elongatus. 

 Pimelodus elongatus, Giinth. Proc. Zool. Soc. 1860, p. 238. pi. 10. fig. B. 

 B. 6. D. 1/6. A. 11. P. 1/9. 



Head covered with a very thin membrane above ; occipital process 

 narrow, elongate, extending on to the small triangular basal bone of 

 the dorsal spine. Adipose fin long, two-sevenths of the total length 

 (without caudal) ; its distance from the dorsal fin is less than the 

 length of the latter. The maxillary barbels extend nearly to the 

 extremity, the outer ones of the mandible to the root of the pec- 

 toral fin. 



The height of the body is one-sixth of the total length (without 

 caudal), the length of the head rather more than one-fifth. The 

 upper jaw is the longer ; the eye is somewhat behind the middle of 

 the length of the head, of which its diameter is one-fourth; the 

 width of the interorbital space is rather more than the diameter of 

 the eye. Dorsal fin higher than long; its spine is slender, two- 

 thirds of the length of the head, and longer than that of the pectoral 

 fin. Caudal fin cleft nearly to the base, with the upper lobe longer. 

 An ill-defined blackish streak along the lateral line. 



Esmeraldas. 



a-b, c-f, g-Jc. Types of the species. From Mr. Fraser's Collection. 



7. Pimelodus lateristriga. 

 Pimelodus lateristrigus, Mull. 8f Trosch. Hor. Ichth. iii. p. 3. 

 D. 1/6. A. 12. P. 1/9. 



Head naked above ; occipital process narrow, elongate, thrice as 

 long as broad, extending on to the small triangular basal bone of 

 the dorsal spine. Adipose fin long, two-sevenths of the total length 

 (without caudal) ; its distance from the dorsal is equal to, or rather 

 more than, the- length of the latter. The maxillary barbels extend 

 to the origin of the adipose fin, the outer ones of the mandible to the 

 middle of the pectoral. 



The length of the head is one-fifth of the total length (without 

 caudal) ; eyes of moderate size, occupying the middle of the head. 

 Dopsal fin much higher ^than long, with the spine slender, three- 

 fourths of the length of the head. Pectoral spine rather shorter than 

 that of the dorsal fin, strongly serrated along its inner edge, and 

 with a few obtuse denticulations at the extremity of its outer edge. 

 Caudal fin deeply cleft, with the lobes pointed, the upper being the 



