53. PIMELODUS. 131 



as long. The eyes are situated somewhat before the middle of the 

 head ; their diameter is one-fifth of the length of the head, and not 

 quite one-half of the width of the interorbital space. Dorsal fin 

 rounded, as high as long, with the spine very feeble. Pectoral spine 

 very short, not quite one-third of the length of the head. A small 

 porus axillaris. The length of the pectoral is one-half of the distance 

 of its root from that of the ventral. The anal fin does not extend to 

 the vertical from the end of the adipose fin if laid backwards. 

 Caudal fin cleft nearly to the base, its lobes being almost of the same 

 length, contained six times and a half in the total length. Colora- 

 tion uniform dark brown. 

 Guatemala. 



a. Six inches long. Rio de San Geronimo. From Mr. 0. Salvin's 

 Collection. 



32. Pimelodus notatus. 



Schomburgk, Fishes of Guiana, i. p. 181. pi. 7. 



B. 9. D. 7. A. 17. P. 1/9. Vert. 44. 

 Head covered with skin above ; dorsal and pectoral spines feeble, 

 the former sometimes produced into a long filament ; adipose fin but 

 little longer than dorsal, widely separate from it. The maxillary 

 barbels extend to the ventral, those of the mandibles beyond the ex- 

 tremity of the pectoral. Back and dorsal fin with numerous small 

 black spots. (Schomb.) 

 Amazons, Bio Branco. 



b. Dorsal fin with seven or eight soft rays. 



33. Pimelodus polycaulus. 

 D 1/7. A. 15. P. 1/8. V. 6. 



Head covered with soft skin above ; occipital process short, trian- 

 gular. Adipose fin long, its length being contained thrice and a 

 third in the total (without caudal) ; its distance from the dorsal is 

 somewhat more than one-half of its own length. The maxillary 

 barbels extend to the extremity of the pectoral, the outer ones of 

 the mandible to its root. 



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

 caudal), the length of the head one-fifth. The lower jaw is rather 

 shorter than the upper ; the band of intermaxillary teeth is about 

 six times as broad as long. Eyes situated before the middle of the 

 length of the head, their diameter being one-half of the width of the 

 interorbital space. Dorsal fin rounded, higher than long ; its spine, 

 prolonged into a flexible portion, is very short and feeble. Pectoral 

 fin two-thirds of the length of the head ; its spine is short, somewhat 

 longer than the humeral spine. A minute porus axillaris. Ventral 

 fin rather shorter than pectoral ; the posterior anal rays do not ex- 

 tend to the vertical from the end of the adipose fin if laid backwards. 

 Caudal fin two-lobed, the lobes being equal in length, the upper 



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